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 whole-number 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.
|
|
