Double+and+Halve

=The Double and Halve Strategy=

This is a mental math strategy that is first covered in grade five. It is based on the fact that if you double one side of a multiplication question and halve the other side you will still arrive at the same product as the original question. It is very easy to use when you have at least one even number because all even numbers are divisible by two.

=Example:=

8 x 7 = 56 double 7 to make 14, and halve 8 to make 4. 4 x 14 = 56 (the same product as above)

You can also use this strategy over and over for the same question.

4 x 14 = 56

double 14 to make 28, and halve 4 to make 2.

2 x 28 = 56

Check out the screen capture done by Rebecca and Laura media type="file" key="Rebeca & lauras screen capture 7C.wmv"