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*This method will instruct you to write the answer from left to right.
Multiplying
By 125
A. Multiplying by 125 is easy if you know that 125 = 1000 ÷ 8. So to multiply by 125, you should divide by 8 and use the following rules on the remainder (n MOD 8):
1. If (n MOD 8) = 0 then write 000.
2. If (n MOD 8) = 1 then write 125.
3. If (n MOD 8) = 2 then write 250.
4. If (n MOD 8) = 3 then write 375. *Notice this is 125r where r is the remainder.
5. If (n MOD 8) = 4 then write 500.
6. If (n MOD 8) = 5 then write 625.
7. If (n MOD 8) = 6 then write 750.
8. If (n MOD 8) = 7 then write 875.
Ex [1] 125 x 26 =_________.
a) 26 ÷ 8 = 3 with a remainder of 2. Write 3.
b) By (3.) we write 250.
c) The answer is 3250.
Ex [2] 487 x 125 =_________.
a) 487 ÷ 8 = 60 with a remainder of 7. Write 60.
b) By (8.) we write 875.
c) The answer is 60875.