__Math module 1 :__**2 OA 1:**Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.

1

**2.OA.2**

**:**Fluently add and subtract within 20 using mental strategies.2 By end of Grade 2, know from memory all sums of two one-digit numbers.

**2.NBT.5**

**:**Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

Focus Standards for Mathematical Practice

MP.1

**Make sense of problems and persevere in solving them.**Students make math drawings and use recomposing strategies to reason through the relationships in word problems. They write equations and word sentences to explain their solutions.

MP.2

**Reason abstractly and quantitatively.**Students decompose numbers and use the associative property to create equivalent but easier problems, e.g., 25 + 6 = 20 + 5 + 5 + 1. They reason abstractly when they relate subtraction to addition and change 13 – 8 = ___ into an unknown addend, 8 + ___ = 13, to solve.

MP.3

**Construct viable arguments and critique the reasoning of others.**Students explain their reasoning to prove that 9 + 5 = 10 + 4. They communicate how simpler problems embedded within more complex problems enable them to solve mentally, e.g., 8 + 3 = 11, so 68 + 3 = 71.

**MP.7 Look for and make use of structure.**Students use the structure of ten to add and subtract within 20, and later, within 100. E.g., 12 – 8 = 10 – 8 + 2 = 2 + 2, and 92 + 3 = 90 + 2 + 3 = 90 + 5.

__Math module 2 :__2.MD.1 Measure the length of an object by selecting and using appropriate tools such as rulers, yardsticks, meter sticks, and measuring tapes.2.MD.2

**Measure the length of an object twice, using length units of different lengths for the two measurements; describe how the two measurements relate to the size of the unit chosen.**

2.MD.3

**Estimate lengths using units of inches, feet, centimeters, and meters.**

2.MD.4

**Measure to determine how much longer one object is than another, expressing the length difference in terms of a standard length unit.**

2.MD.5

**Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units, e.g., by using drawings (such as drawings of rulers) and equations with a symbol for the unknown number to represent the problem.**

2.MD.6

**Represent whole numbers as lengths from 0 on a number line diagram with equally spaced points corresponding to the numbers 0, 1, 2, …, and represent whole-number sums and differences within 100 on a number line diagram.**

1.MD.1

**Order three objects by length; compare the lengths of two objects indirectly by using a third object.**

1.MD.2

**Express the length of an object as a whole number of length units, by laying multiple copies of a shorter object (the length unit) end to end; understand that the length measurement of an object is the number of same-size length units that span it with no gaps or overlaps.**

*Limit to contexts where the object being measured is spanned by a whole number of length units with no gaps or overlaps.*

MP.2

**Students reason quantitatively when they measure and compare lengths. They reason abstractly when they use estimation strategies such as benchmarks and mental rulers, and when they relate number line diagrams to measurement models.**

**MP.3**Students reason to solve word problems involving length measurement using tape diagrams and also analyze the reasonableness of the work of their peers.

MP.5

**Students consider the object being measured and choose the appropriate measurement tool. They use the tool of the tape diagram to solve word problems.**

MP.6 Students accurately measure by laying physical units end-to-end with no gaps and when using a measurement tool. They correctly align the zero-point on a ruler as the beginning of the total length. They attend to precision when they verbally and in writing specify the length unit, when they use a ruler to measure or draw a straight line of a given length, and when they verify estimations by measuring.

**Math module 3 :**Understand place value.

2.NBT.1 Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones. Understand the following as special cases:

a. 100 can be thought of as a bundle of ten tens – called a “hundred.”

b. The numbers 100, 200, 300, 400, 500, 600, 700, 800, 900 refer to one, two, three, four, five, six, seven, eight, or nine hundreds (and 0 tens and 0 ones).

2.NBT.2 Count within 1000; skip-count by 5s[1], 10s and 100s.

**2.NBT.3**Read and write numbers to 1000 using base-ten numerals, number names, and expanded form.

2.NBT.4 Compare two three-digit numbers based on meanings of the hundreds, tens, and ones digits, using >, =, and < symbols to record the results of comparisons.

**Math module 4 :**Represent and solve problems involving addition and subtraction.

**2.OA.1**Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.

Use place value understanding and properties of operations to add and subtract.

**[1]**

**2.NBT.5**Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

**2.NBT.6**Add up to four two-digit numbers using strategies based on place value and properties of operations.

**2.NBT.7**Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in 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.NBT.8**Mentally add 10 or 100 to a given number 100–900, and mentally subtract 10 or 100 from a given number 100–900.

**2.NBT.9**Explain why addition and subtraction strategies work, using place value and the properties of operations. (Explanations may be supported by drawings or objects.)

**2.NBT.1**Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones. Understand the following as special cases:

a. 100 can be thought of as a bundle of ten tens – called a “hundred.”

b. The numbers 100, 200, 300, 400, 500, 600, 700, 800, 900 refer to one, two, three, four, five, six, seven, eight, or nine hundreds (and 0 tens and 0 ones).

**2.NBT.2**Count within 1000; skip-count by 5s, 10s, and 100s.

**2.NBT.3**Read and write numbers to 1000 using base-ten numerals, number names, and expanded form.

**Math module 5 :**Use place value understanding and properties of operations to add and subtract.

**2.NBT.7**Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in 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.NBT.8**Mentally add 10 or 100 to a given number 100–900, and mentally subtract 10 or 100 from a given number 100–900.

**2.NBT.9**Explain why addition and subtraction strategies work, using place value and the properties of operations. (Explanations may be supported by drawings or objects.)

**2.NBT.1**Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones. Understand the following as special cases:

a. 100 can be thought of as a bundle of ten tens—called a “hundred.”

b. The numbers 100, 200, 300, 400, 500, 600, 700, 800, 900 refer to one, two, three, four, five, six, seven, eight, or nine hundreds (and 0 tens and 0 ones).

**2.NBT.2**Count within 1000; skip-count by 5s, 10s, and 100s.

**2.NBT.3**Read and write numbers to 1000 using base-ten numerals, number names, and expanded form.

**2.NBT.5**Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

**Math Module 6 :**Work with equal groups of objects to gain foundations for multiplication.

2.OA.3 Determine whether a group of objects (up to 20) has an odd or even number of members, e.g., by pairing objects or counting them by 2s; write an equation to express an even number as a sum of two equal addends.

2.OA.4 Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns; write an equation to express the total as a sum of equal addends.

Reason with shapes and their attributes.

**[1]**

2.G.2 Partition a rectangle into rows and columns of same-size squares and count to find the total number of them.

[1] 2.G.2 is included in this module because the array model is so important to the foundation for multiplication. The balance of this cluster is addressed in Module 8.

2.NBT.2 Count within 1000; skip-count by 5s, 10s, and 100s.

2.NBT.6 Add up to four two-digit numbers using strategies based on place value and properties of operations.

Focus Standards for Mathematical Practice

MP.3

**Construct viable arguments and critique the reasoning of others.**Students explain their thinking using drawings, models, and equations to lay the conceptual foundation for multiplication and division. “If I build an array with 3 columns of 4 objects, then I must have twelve objects, because 4 + 4 + 4 = 12. Likewise, if I partition my rectangle into twelve equally sized tiles, I can make 3 equal groups of 4 tiles, or I can make 4 equal groups of 3 tiles.” Students also defend their reasoning as they prove that a number is even or odd, making connections to the previous concepts of counting by twos, adding on, equal groups, and doubles.

MP.4

**Model with mathematics.**Students learn to organize a set of objects into equal groups and then into rows and columns, or rectangular arrays. They use math drawings to analyze the relationship between rows and columns (e.g., 3 rows of 4, or 4 columns of 3) and to model the array as the sum of equal addends (e.g., 4 + 4 + 4 = 12).

MP.7

**Look for and make use of structure.**As students compose and decompose arrays, they recognize that the array structure is a collection of rows or columns and that either can be seen as a unit. Students match repeated addition to both the structure of the rows and columns, e.g., 5 + 5 + 5 can be 3 rows or columns of 5, or 3 fives.

MP.8

**Look for and express regularity in repeated reasoning.**As students create equal groups using objects, they recognize that they are repeatedly adding the same number, e.g., 3 groups of 4 bears can be expressed as 4 + 4 + 4. Students also discover patterns in odd and even numbers, recognizing the repetition of 0, 2, 4, 6, and 8 in the ones place.

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