Mental Math Strategy: Compensation

The video introduces the mental math strategy of compensation, focusing on subtracting numbers close to 10 or 20, such as 8, 9, 18, and 19. It emphasizes the importance of understanding the concept over memorizing the name. The strategy involves adjusting a number to make calculations easier and then compensating for that adjustment. Concrete examples using a reckon rack and representational examples using a number line are provided. The video concludes by highlighting the strategy's transferability to other numbers and the importance of starting with concrete experiences.

What is the main idea behind the compensation strategy?

• Using multiplication to simplify addition.

• Adding numbers in a sequence to simplify subtraction.

• Adjusting one number to make calculations easier and then correcting the adjustment.

• Dividing numbers to make subtraction easier.

Why is it important not to get hung up on the names of strategies?

• Because names are irrelevant in math.

• Because the names are too complicated.

• Because students should create their own names.

• Because the idea behind the strategy is more important.

In the example of 26 subtract 9, what is the first step?

• Subtracting 9 directly.

• Subtracting 10 instead of 9.

• Multiplying 26 by 9.

• Adding 10 to 26.

After subtracting 10 from 26, what must be done to correct the calculation?

• Divide the result by 2.

• Multiply the result by 2.

• Subtract 1 from the result.

• Add 1 back to the result.

In the example of 43 subtract 8, what is the initial adjustment made?

• Subtracting 8 directly.

• Multiplying 43 by 8.

• Subtracting 10 instead of 8.

• Adding 10 to 43.

How do you correct the calculation after subtracting 10 from 43?

• Divide the result by 2.

• Multiply the result by 2.

• Subtract 2 from the result.

• Add 2 back to the result.

What does the 'C' in the CRA model stand for?

• Compensation

• Correction

• Calculation

• Concrete

In the number line example, what is the first step to solve 53 subtract 18?

• Multiply 53 by 18.

• Add 20 to 53.

• Subtract 20 instead of 18.

• Subtract 18 directly.

Why is it important to start with concrete experiences when teaching compensation?

• Because concrete experiences are faster.

• Because students dislike abstract concepts.

• Because abstract concepts are too easy.

• Because it makes the strategy more visual and understandable.

How does the compensation strategy help with mental math?

• It requires memorizing more steps.

• It makes calculations more complex.

• It simplifies calculations by using friendly numbers.

• It only works for addition.