Multiplying by 9

A trick to multiplying by 9.  First subtract the number that you are multiplying by and subtract 1 from it.  Put that number in the "tens" place and then subtract the new number from 9.  This number goes in the "ones" place.

• For this example we will use 9 X 5
• Subtract 1 from 5 you get 4
• Place the 4 in the "tens" place
• Then subtract the 4 from 9 you get 5
• Place the 5 in the "ones" place
• Your answer to 9 X 5 is 45

Hint:  This trick will work for number multiplied by 9 ranging from 0 to 9.