The Common Core in Maryland

2.NOS Number and Operation Sense

• 2.NOS.A Understand place value and representations of numbers.

  • 2.NOS.A.1 Use understanding of 100 as a bundle of ten tens, called a "hundred," and compose and decompose three-digit numbers.

    • 2.NOS.A.1.a Compose and decompose three-digit numbers into hundreds, tens, and ones by using objects, drawings, and/or equations.

      • Place value models - up to hundreds (2-L.2)
      • Convert to/from a number - tens and ones (2-L.8)
      • Convert to/from a number - up to hundreds (2-L.11)
      • Convert from expanded form - up to hundreds (2-L.14)
      • Convert between standard and expanded form (2-L.15)

    • 2.NOS.A.1.b Describe a given number as the correct number of hundreds, tens, and ones.

      • Convert to/from a number - up to hundreds (2-L.11)
      • Convert between place values - ones and hundreds (2-L.12)
      • Convert between place values - ones, tens, and hundreds (2-L.13)

    • 2.NOS.A.1.c Compose and decompose three-digit numbers in more than one way.

      • Regroup tens and ones - ways to make a number (2-L.9)
      • Regroup tens and ones (2-L.10)
      • Regroup hundreds, tens, and ones - ways to make a number (2-L.16)

  • 2.NOS.A.2 Count forward and backward within 1000 starting with any number.

    • 2.NOS.A.2.a Skip-count forward and backwards by 2s, 5s, 10s, and 100s.

      • Count forward - up to 1,000 (2-A.4)
      • Skip-count by twos (2-C.1)
      • Skip-count by fives (2-C.2)
      • Skip-count by tens (2-C.3)
      • Skip-count by fives and tens (2-C.4)
      • Count forward and backward by fives and tens (2-C.8)
      • Count forward and backward by twos, fives, and tens (2-C.9)
      • Count forward by tens - up to 1,000 (2-C.11)
      • Count forward by fives, tens, and hundreds (2-C.12)
      • Count forward and backward by fives, tens, and hundreds (2-C.13)
      • Count forward and backward by twos, fives, tens, and hundreds (2-C.14)

    • 2.NOS.A.2.b Use skip-counting to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns.

  • 2.NOS.A.3 Read and write numbers within 1000 using base-ten numerals, number names, and expanded form.

    • Spell word names for numbers up to 20 (2-D.1)
    • Writing numbers up to 100 in words - convert words to digits (2-D.2)
    • Writing numbers up to 100 in words - convert digits to words (2-D.3)
    • Writing numbers up to 1,000 in words - convert words to digits (2-D.4)
    • Writing numbers up to 1,000 in words - convert digits to words (2-D.5)
    • Writing numbers up to 1,000 in words (2-D.6)
    • Convert from expanded form - up to hundreds (2-L.14)
    • Convert between standard and expanded form (2-L.15)

  • 2.NOS.A.4 Compare two numbers within 1000 by reasoning about the values of the hundreds, tens, and ones digits and/or the location of the numbers on a number line. Record the results of comparisons with the symbols >, =, and <.

    • Comparing numbers up to 1,000 (2-B.3)

  • 2.NOS.A.5 Estimate quantities by reasoning about their location on a number line, their relationship to benchmark numbers, and to assess reasonableness of sums and differences.

    • Estimate sums (2-Z.4)
    • Estimate differences (2-Z.5)

• 2.NOS.B Add and subtract within 20.

  • 2.NOS.B.6 Recall or quickly derive addition and subtraction facts within 20.

    • Add one-digit numbers - sums to 10 (2-G.1)
    • Add one-digit numbers - sums to 20 (2-G.2)
    • Sort addition facts - sums to 20 (2-G.3)
    • Which addition sentence is true? - sums to 20 (2-G.8)
    • Add three one-digit numbers (2-G.9)
    • Subtract one-digit numbers - up to 10 (2-I.1)
    • Subtract a one-digit number from a two-digit number up to 20 (2-I.2)
    • Which subtraction sentence is true? - up to 20 (2-I.7)
    • Addition and subtraction - up to 20 (2-J.2)
    • Ways to make a number using addition and subtraction - up to 20 (2-J.3)
    • Which addition or subtraction sentence is true? - up to 20 (2-J.5)
    • Ways to make a number using addition - sums to 10 (2)
    • Ways to make a number using subtraction - up to 10 (2)

    • 2.NOS.B.6.a Use counting, make ten, and ten more/less, doubling strategies to add and subtract.

      • Add doubles using models (2-F.1)
      • Add doubles (2-F.2)
      • Add doubles - complete the sentence (2-F.3)
      • Add by counting on - sums to 20 (2-F.6)
      • Subtract doubles (2-H.1)
      • Subtract by counting back - up to 20 (2-H.3)
      • Subtract by counting on - up to 20 (2-H.5)

    • 2.NOS.B.6.b Use the use ten strategy and doubles plus one strategy to add and subtract.

      • Add near doubles (2-F.4)
      • Make ten to add (2-F.7)
      • Use ten to subtract (2-H.4)
      • Count on and use ten to subtract - up to 20 (2-H.6)

    • 2.NOS.B.6.c Use the inverse operation to add and subtract.

      • Add one-digit numbers - sums to 20 (2-G.2)
      • Sort addition facts - sums to 20 (2-G.3)
      • Complete the addition sentence - sums to 20 (2-G.6)
      • Subtract by counting on - up to 20 (2-H.5)
      • Complete the subtraction sentence - up to 20 (2-I.5)
      • Add in any order (2-Y.1)

• 2.NOS.C Use representations, place value understanding, and properties of operations to add and subtract.

  • 2.NOS.C.7 Represent whole number sums and differences within 100 using lengths on a number line.

    • Addition sentences using number lines - sums to 20 (2-F.5)
    • Subtraction sentences using number lines - up to 20 (2-H.2)
    • Addition and subtraction sentences using number lines - up to 20 (2-J.1)
    • Use number lines to add two-digit numbers (2-M.4)
    • Use number lines to subtract two-digit numbers (2-O.4)

  • 2.NOS.C.8 Fluently add and subtract within 100.

    • 2.NOS.C.8.a Use strategies based on counting and place value to add and subtract.

      • Break apart a one-digit number to add (2-M.1)
      • Use models to add a two-digit and a one-digit number - without regrouping (2-M.2)
      • Use models to add a two-digit and a one-digit number - with regrouping (2-M.3)
      • Break apart a two-digit number to add - sums to 100 (2-M.5)
      • Use compensation to add on a number line - up to two digits (2-M.6)
      • Use compensation to add - up to two digits (2-M.7)
      • Use models to add two-digit numbers - without regrouping (2-M.8)
      • Use models to add two-digit numbers - with regrouping (2-M.9)
      • Use place value to add two-digit numbers - without regrouping (2-M.10)
      • Use place value to add two-digit numbers - with regrouping (2-M.11)
      • Break apart a one-digit number to subtract (2-O.1)
      • Use models to subtract a one-digit number from a two-digit number - without regrouping (2-O.2)
      • Use models to subtract a one-digit number from a two-digit number - with regrouping (2-O.3)
      • Break apart a two-digit number to subtract (2-O.5)
      • Use compensation to subtract on a number line - up to two digits (2-O.6)
      • Use compensation to subtract - up to two digits (2-O.7)
      • Use models to subtract two-digit numbers - without regrouping (2-O.9)
      • Use models to subtract two-digit numbers - with regrouping (2-O.10)
      • Use place value to subtract two-digit numbers - without regrouping (2-O.11)
      • Use place value to subtract two-digit numbers - with regrouping (2-O.12)

    • 2.NOS.C.8.b Use properties of operations, and the inverse relationship between addition and subtraction to add and subtract.

      • Add a two-digit and a one-digit number - without regrouping (2-N.1)
      • Add a two-digit and a one-digit number - with regrouping (2-N.2)
      • Add a multiple of 10 to a two-digit number (2-N.3)
      • Add two-digit numbers without regrouping - sums to 100 (2-N.4)
      • Add two-digit numbers with regrouping - sums to 100 (2-N.5)
      • Add two-digit numbers - sums to 100 (2-N.6)
      • Add two-digit numbers vertically - sums to 100 (2-N.7)
      • Ways to make a number using addition (2-N.9)
      • Complete the addition sentence - up to two digits (2-N.10)
      • Subtract a one-digit number from a two-digit number - without regrouping (2-P.1)
      • Subtract a one-digit number from a two-digit number - with regrouping (2-P.2)
      • Subtract a one-digit number from a two-digit number (2-P.3)
      • Subtract a multiple of 10 from a two-digit number (2-P.4)
      • Subtract two-digit numbers - without regrouping (2-P.5)
      • Subtract two-digit numbers - with regrouping (2-P.6)
      • Subtract two-digit numbers (2-P.7)
      • Subtract two-digit numbers vertically (2-P.8)
      • Ways to make a number using subtraction (2-P.9)
      • Complete the subtraction sentence - up to two digits (2-P.11)
      • Add and subtract numbers - up to 100 (2-Q.1)
      • Which sign (+ or -) makes the number sentence true? - up to 100 (2-Q.3)
      • Ways to make a number using addition and subtraction - up to 100 (2-Q.4)
      • Relate addition and subtraction sentences - up to two digits (2-Q.5)
      • Complete the addition or subtraction sentence - up to 100 (2-Q.6)
      • Which addition or subtraction equation is true? - up to 100 (2-Q.8)

    • 2.NOS.C.8.c Determine and explain when a strategy is most efficient.

  • 2.NOS.C.9 Add and subtract within 1000, recognizing that when adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.

    • 2.NOS.C.9.a Use concrete models or drawings to add and subtract.

      • Use number lines to add three-digit numbers (2-S.1)
      • Use models to add three-digit numbers - without regrouping (2-S.4)
      • Use models to add three-digit numbers - with regrouping (2-S.5)
      • Use number lines to subtract three-digit numbers (2-U.1)
      • Use models to subtract from three-digit numbers - without regrouping (2-U.4)
      • Use models to subtract from three-digit numbers - with regrouping (2-U.5)

    • 2.NOS.C.9.b Use strategies based on place value (counting on, partial sums, making tens, etc.) to add and subtract.

      • Regroup tens and ones - ways to make a number (2-L.9)
      • Regroup tens and ones (2-L.10)
      • Regroup hundreds, tens, and ones - ways to make a number (2-L.16)
      • Break apart a three-digit number to add (2-S.2)
      • Use compensation to add - up to three digits (2-S.3)
      • Use expanded form to add three-digit numbers - without regrouping (2-S.6)
      • Use expanded form to add three-digit numbers - with regrouping (2-S.7)
      • Use expanded form to add three-digit numbers (2-S.8)
      • Add a multiple of 100 to a three-digit number (2-T.2)
      • Add a multiple of 10 or 100 to a three-digit number (2-T.3)
      • Addition with three-digit numbers - without regrouping (2-T.4)
      • Addition with three-digit numbers - with regrouping (2-T.5)
      • Break apart a three-digit number to subtract (2-U.2)
      • Use compensation to subtract - up to three digits (2-U.3)
      • Use expanded form to subtract three-digit numbers - without regrouping (2-U.6)
      • Use expanded form to subtract three-digit numbers - with regrouping (2-U.7)
      • Use expanded form to subtract three-digit numbers (2-U.8)
      • Subtract a multiple of 100 from a three-digit number (2-V.2)
      • Subtract a multiple of 10 or 100 from a three-digit number (2-V.3)
      • Subtract across zeros (2-V.4)
      • Subtract from three-digit numbers - without regrouping (2-V.5)
      • Subtract from three-digit numbers - with regrouping (2-V.6)
      • Subtract from three-digit numbers (2-V.7)
      • Subtract from three-digit numbers vertically (2-V.8)
      • Subtraction word problems - up to three digits (2-V.9)
      • Break apart a three-digit number to add or subtract (2-W.1)
      • Use compensation to add or subtract - up to 1,000 (2-W.2)
      • Add and subtract numbers up to 1,000 (2-W.3)
      • Add and subtract with three-digit numbers vertically (2-W.4)
      • Addition and subtraction word problems - up to 1,000 (2-W.5)

    • 2.NOS.C.9.c Use properties of operations, and/or the relationship between addition and subtraction to add and subtract.

      • Complete the addition sentence - up to three digits (2-T.9)
      • Complete the subtraction sentence - up to three digits (2-V.10)

    • 2.NOS.C.9.d Represent and explain the calculation by connecting the strategy used to the meaning of addition and subtraction.

      • Related addition facts (2-Y.2)
      • Related subtraction facts (2-Y.3)
      • Fact families (2-Y.4)
      • Fact families - up to 100 (2)

  • 2.NOS.C.10 Mentally add and subtract 10 or 100 to a given number 100-900.

    • Add 10 or 100 to a three-digit number (2-T.1)
    • Subtract 10 or 100 from a three-digit number (2-V.1)

• 2.NOS.D Understand equal parts of a whole.

  • 2.NOS.D.11 Partition circles and rectangles into equal shares (halves, thirds, and fourths) recognizing that equal shares do not need to have the same shape. Determine how many equal shares are needed to make a whole.

    • Equal parts (2-LL.1)
    • Identify halves (2-LL.2)
    • Identify thirds (2-LL.3)
    • Identify fourths (2-LL.4)
    • Identify halves, thirds, and fourths (2-LL.5)
    • Make halves (2-LL.6)
    • Make thirds (2-LL.7)
    • Make fourths (2-LL.8)
    • Make halves, thirds, and fourths (2-LL.9)
    • Make halves, thirds, and fourths in different ways (2-LL.10)
    • Identify a half, a third, and a fourth (2-LL.11)

2.AT Algebraic Thinking

• 2.AT.A Solve problems involving addition and subtraction.

  • 2.AT.A.1 Use addition and subtraction within 100 to solve one-step problems in context involving an unknown in any situation or position by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

    • Addition word problems - sums to 20 (2-G.4)
    • Addition sentences for word problems - sums to 20 (2-G.5)
    • Addition word problems - three one-digit numbers (2-G.10)
    • Addition word problems - four or more one-digit numbers (2-G.12)
    • Subtraction word problems - up to 20 (2-I.3)
    • Subtraction sentences for word problems - up to 20 (2-I.4)
    • Comparison word problems - up to 20 (2-K.1)
    • Use models to solve addition and subtraction word problems - up to 20 (2-K.2)
    • Addition and subtraction word problems - up to 20 (2-K.3)
    • Write number sentences for word problems - up to 20 (2-K.4)
    • Match word problems to addition and subtraction sentences - up to 20 (2-K.5)
    • Solve word problems using guess-and-check - up to 20 (2-K.7)
    • Addition word problems - up to two digits (2-N.8)
    • Write the addition sentence - up to two digits (2-N.11)
    • Addition word problems - three numbers up to two digits each (2-N.16)
    • Addition word problems - four numbers up to two digits each (2-N.19)
    • Subtraction word problems - up to two digits (2-P.10)
    • Write the subtraction sentence - up to two digits (2-P.12)
    • Use models to solve addition and subtraction word problems - up to 100 (2-R.1)
    • Addition and subtraction word problems - up to 100 (2-R.2)
    • Match addition and subtraction word problems to equations - up to 100 (2-R.3)

  • 2.AT.A.2 Use addition and/or subtraction within 100 to solve two-step problems in context involving any situation or position of an unknown by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

    • Two-step addition and subtraction word problems - up to 20 (2-K.6)
    • Two-step addition and subtraction word problems - up to 100 (2-R.4)

• 2.AT.B Recognize patterns in numbers.

  • 2.AT.B.3 Determine whether a group of objects within 20 has an odd or even number of members. Write an equation to express an even number as a sum of two equal addends.

    • Even or odd number of shapes - up to 20 (2-E.1)
    • Identify even and odd numbers - up to 20 (2-E.2)
    • Addition sentences for even and odd numbers (2-E.3)
    • Add doubles - complete the sentence (2-F.3)

2.GR Geometric Reasoning and Measurement

• 2.GR.A Measure and estimate lengths in standard units.

  • 2.GR.A.1 Measure the length of an object to the nearest whole unit by using appropriate tools.

    • Measure using an inch ruler (2-GG.2)
    • Choose the best measuring tool: customary units of length (2-GG.9)
    • Measure using a centimeter ruler (2-HH.1)
    • Choose the best measuring tool: metric units of length (2-HH.6)

  • 2.GR.A.2 Measure the length of an object twice using different length units. Compare the two measurements relative to the size of the unit chosen.

    • Measure with different customary units: inches, feet, and yards (2-GG.6)
    • Which customary unit of length is appropriate: inches, feet, or yards? (2-GG.8)
    • Measure with different metric units (2-HH.4)
    • Which metric unit of length is appropriate? (2-HH.5)

  • 2.GR.A.3 Estimate lengths using units of inches, feet, centimeters, and meters.

    • Estimate lengths with inches and feet (2-GG.4)
    • Which customary unit of length is appropriate: inches or feet? (2-GG.7)
    • Estimate lengths with centimeters and meters (2-HH.3)
    • Which metric unit of length is appropriate? (2-HH.5)

  • 2.GR.A.4 Measure to determine how much longer one object is than another, expressing the difference in length in terms of a standard-length unit.

    • Measure to compare length in inches (2-GG.3)
    • Measure to compare length in centimeters (2-HH.2)

• 2.GR.B Reason with shapes and their attributes.

  • 2.GR.B.5 Identify and draw shapes (triangles, quadrilaterals, pentagons, hexagons, and cubes) having specific attributes, such as a given number of angles or a given number of equal faces.

    • Count sides and vertices (2-II.1)
    • Identify quadrilaterals (2-II.2)
    • Identify pentagons (2-II.3)
    • Name polygons: up to 6 sides (2-II.4)
    • Classify polygons: up to 6 sides (2-II.5)
    • Sort two-dimensional shapes (2-II.8)
    • Draw polygons (2-II.9)
    • Cubes (2-JJ.1)
    • Count vertices, edges, and faces (2-JJ.4)
    • Compare vertices, edges, and faces (2-JJ.5)
    • Identify faces of three-dimensional shapes (2-JJ.6)
    • Identify shapes traced from solids (2-JJ.7)
    • Sort three-dimensional shapes (2-JJ.8)
    • Compare sides and vertices (2)

  • 2.GR.B.6 Explain that a line of symmetry for a two-dimensional figure is a line across the figure such that the figure can be folded along the line into matching parts. Identify line-symmetric figures and draw lines of symmetry.

    • Identify lines of symmetry (2)
    • Draw a line of symmetry (2)
    • Symmetry (2)

• 2.GR.C Work with time and money.

  • 2.GR.C.7 Tell and represent time to the nearest minute using multiple representations.

    • Match digital clocks and times (2-DD.1)
    • Match analog clocks and times (2-DD.2)
    • Match analog and digital clocks (2-DD.3)
    • Read clocks and write times: hour and half hour (2-DD.4)
    • Read clocks and write times (2-DD.5)
    • Match analog clocks and times to the minute (2)
    • Match analog and digital clocks to the minute (2)
    • Read analog clocks and write times to the minute (2)

  • 2.GR.C.8 Estimate and calculate elapsed time to the hour and half hour.

    • Elapsed time word problems: find the elapsed time (2)

  • 2.GR.C.9 Count mixed sets of coins and bills to solve problems in context (within $20.00) involving bills, quarters, dimes, nickels, and pennies, using $ and ¢ symbols appropriately.

    • Names and values of common coins (2-AA.1)
    • Count money - groups of like coins (2-AA.3)
    • Count money - pennies, nickels, and dimes only (2-AA.4)
    • Count money up to $1 (2-AA.5)
    • Equivalent amounts of money up to $1 (2-AA.6)
    • Exchanging money - with pictures (2-AA.7)
    • Exchanging money (2-AA.8)
    • Exchanging money II (2-AA.9)
    • Least number of coins (2-AA.10)
    • Do you have enough money? - up to $1 (2-AA.11)
    • How much more to make a dollar? (2-AA.12)
    • Correct amount of change (2-AA.13)
    • Making change (2-AA.14)
    • Add money up to $1 (2-BB.1)
    • Add money up to $1: word problems (2-BB.2)
    • Subtract money up to $1 (2-BB.3)
    • Subtract money up to $1: word problems (2-BB.4)
    • Add and subtract money up to $1 (2-BB.5)
    • Add and subtract money up to $1: word problems (2-BB.6)
    • Which picture shows more? - up to $5 (2-CC.3)

2.DS Reasoning with Data and Statistics

• 2.DS.A Represent and interpret data.

  • 2.DS.A.1 Ask and answer questions by collecting, organizing, and summarizing data.

    • 2.DS.A.1.a Craft a question that can be answered by collecting categorical and numerical data.

    • 2.DS.A.1.b Collect and organize data using surveys, making observations, or measuring.

    • 2.DS.A.1.c Represent categorical data using picture graphs and bar graphs. Represent numerical data using line plots.

      • Create picture graphs (2-FF.3)
      • Create bar graphs (2-FF.7)
      • Which bar graph is correct? (2-FF.10)

    • 2.DS.A.1.d Summarize the data presented in data visualizations using "most," "least," "greater than," "less than," and "equal to" and determine what questions can be answered with a given data set.

      • Interpret picture graphs (2-FF.4)
      • Interpret bar graphs II (2-FF.9)