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*This method will instruct you to write the answer from left to right.
When multiplying by 5, it is easier to divide by 2 and multiply by 10.
If the number you are multiplying is odd, then the last number will be a 5 (see Ex [2]), otherwise the last number is 0.
Ex [1] 5 x 142 =_________.
a) 142 ÷ 2 = 71. Write 71.
b) Since 142 is even the last number is 0. Write 0.
c) The answer is 710.
Ex [2] 5 x 142857 =_______.
a) 142857 ÷ 2 = 71428 with a remainder of 1. Write 71428.
b) Since there is a remainder of 1, the last number is 5. Write 5.
c) The answer is 714285.
Note: This trick works because 5 = 10 ÷ 2.