MathNinja.Org

Skip to comment form

What if they whole numbers were different?

Say like 10 5/8 x 9 3/8.

Then kinda think of it as FOIL. the problem you gave doesnt tend to happen. 10 5/8 x 8 3/5 is more realistic. You would notice that the can take 3/5 of 10 and 5/8 of 8. Just FOIL it.

There is another way too. You see that each number is 5/8 away from 10 well square 10 and square 5/8 and subtract. So 100-25/64=99 49/64

Bah you are right , that a new trick this year I am still not spotting it.

Your email address will not be published.

## 4 comments

Skip to comment form

What if they whole numbers were different?

Say like 10 5/8 x 9 3/8.

Author

Then kinda think of it as FOIL. the problem you gave doesnt tend to happen.

10 5/8 x 8 3/5 is more realistic. You would notice that the can take 3/5 of 10 and 5/8 of 8. Just FOIL it.

There is another way too. You see that each number is 5/8 away from 10 well square 10 and square 5/8 and subtract. So 100-25/64=99 49/64

Author

Bah you are right , that a new trick this year I am still not spotting it.