3.o Decompose numbers less than or equal to 10 into pairs in more than one way, e.g., by using objects or drawings, and
record each decomposition by a drawing or equation (e.g., 5 = 2 + 3 and 5 = 4 + 1).

Understand and apply properties of operations and the relationship between addition and subtraction.
3. Apply properties of operations as strategies to add and subtract.3 Examples: If 8 + 3 = 11 is known, then 3 + 8 = 11 is also
known. (Commutative property of addition.) To add 2 + 6 + 4, the second two numbers can be added to make a ten, so 2 + 6 + 4 = 2 + 10 = 12. (Associative property of addition.)

Work with equal groups of objects to gain foundations for multiplication.
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.

3. Use multiplication and division within 100 to solve word problems in situations involving equal groups, arrays, and measure
ment quantities, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.1

3. Solve multistep word problems posed with whole numbers and having wholenumber answers using the four operations,
including problems in which remainders must be interpreted. Represent these problems using equations with a letter
standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation
strategies including rounding.

3. Generate two numerical patterns using two given rules. Identify apparent relationships between corresponding terms. Form
ordered pairs consisting of corresponding terms from the two patterns, and graph the ordered pairs on a coordinate plane. For example, given the rule “Add 3” and the starting number 0, and given the rule “Add 6” and the starting number 0,
generate terms in the resulting sequences, and observe that the terms in one sequence are twice the corresponding terms
in the other sequence. Explain informally why this is so.
