Multiplication Number Sense Trick

We're now on Part 3 of our Number Sense #MathTricks on Facebook.  After watching our video, use the material below to get in some extra practice.

Our secret for making mental math a breeze is using what we call " friendly numbers".  Friendly Numbers are multiples of 10.  So when multiplying, we look for pairs that make a multiple of 10. 

In our example, we we can pair 5 × 2 to make 10. 

That leaves 4 × 3 which is 12.

Then we pair up those pairs 12 × 10 =120 and anything times 1 is itself.

So 5 × 4 × 3 × 2 × 1 is 120!

If you think you've got the hang of it, try out the practice problems below!