Unit B

What Strategies Can I Use to Add and Subtract?

This unit will allow us to investigate more than one strategy to solve problems.

Some KEY VOCABULARY in this unit will be: strategy, efficient, fluency, equation, related fact(s), fact families, make-a-ten, doubles, doubles plus 1, doubles minus 1, count on, count back

In this unit, one essential focus is to move away from counting all in two groups.   

One strategy that will help us do so is the COUNTING ON strategy.

th-1This sure does beat holding up 6 fingers and holding up 5 fingers….then, realizing you don’t have anymore fingers!

Although this strategy is beneficial, it is not efficient when adding more than 3 numbers. It also prevents students from mastering basic facts.

Another strategy is COUNTING BACK.  This strategy helps us when subtracting.

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We want students to explore all strategies and learn when counting on is no longer efficient. At this time, your child may begin to use the other strategies below.

Doubles Facts are typically easy facts for students to learn.

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They can use that understanding to investigate NEAR DOUBLES

(some may call this strategy Doubles +1 or Doubles -1)

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We use this strategy when adding two consecutive numbers, in other words two numbers that follow each other. This is where students use their knowledge of doubles to work out the answer.

For example, the problem might be 5 + 6 =

This is the same as 5 + 5 + 1 = 11 or 6 + 6 – 1 = 11.

Having an understanding of the ORDER PROPERTY (communicative property), or changing the order of the addends, gives students another strategy to help solve addition problems.

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FACT FAMILIES show us how addition and subtraction are related.

A family of facts

A family of facts

Make a Ten