Change the mixed number into improper fraction, so that we can answer it easily.
To change a mixed number into a improper fraction, the formula is:
dw + n = new numerator
wherein
d = denominator
w = whole number
n = numerator
Performing the operation:
7 1/7 as a improper fraction is:
7 x 7 + 1 = 50/7
2 5/8 as a improper fraction is:
8 x 2 + 5 = 21/8
Now our fraction can be answered properly, and easily.
50/7 - 21/8 = ?
Find the LCD.
7 : 7, 14, 21, 28, 35, 42, 49, 56
8 : 8, 16, 24, 32, 40, 48, 56
So 56 is the LCD of 50/7 and 21/8
56 is going to be our denominator in our answer.
56 / 7 x 50 = 400
56 / 8 x 21 = 147
400 - 147 is 253
So the answer is 253/56
Re-writing as a mixed number:
4 29/56
is the answer
