From the BEATCALC
mailing list:
a weekly service from B. Lee Clay,
archived here by the Math Forum.
To subscribe to the BEATCALC mailing list,
write to BEATCALC@aol.com.
Dividing a 2-digit number by 1 1/4
Select a 2-digit number.
Multiply by 8.
Move the decimal point one place to the left.
Example:
The 2-digit number chosen to divide by 1 1/4 is 32.
Multiply by 8: 8 x 32 = 240 + 16 = 256
Move the decimal point one place to the left: 25.6
So 32 divided by 1 1/4 = 25.6.
See the pattern?
The 2-digit number chosen to divide by 1 1/4 is 64.
Multiply by 8: 8 x 64 = 480 + 32 = 512
Move the decimal point one place to the left: 51.2
So 64 divided by 1 1/4 = 51.2.
Multiply from left to right for ease and accuracy. You will soon be
doing this division by a mixed number quickly.