Exploration of Addition and Subtraction Strategies

How does the number line help in solving 66 + 21?

• By subtracting smaller numbers first

• By directly adding the numbers

• By multiplying the numbers

• By using rainbow hops to add place values

What is the first step in using the number line to subtract 66 - 21?

• Add the numbers together

• Start with the largest number

• Subtract the ones first

• Start with the smaller number

How does the commutative property simplify 66 + 21?

• By subtracting 21 from 66

• By multiplying 66 by 21

• By adding 21 directly to 66

• By changing 21 to 20 and adjusting 66

What adjustment is made to solve 66 - 21 using the commutative property?

• Change 21 to 22

• Multiply 66 by 21

• Change 21 to 20 and adjust 66

• Add 21 to 66

How are base 10 blocks used to solve 66 + 21?

• By subtracting blocks from each other

• By representing numbers with blocks and counting them

• By drawing a number line

• By using the commutative property