Subtract 21/80 from 18/70
18/70 - 21/80 is -3/560.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 80 is 560
Next, find the equivalent fraction of both fractional numbers with denominator 560 - For the 1st fraction, since 70 × 8 = 560,
18/70 = 18 × 8/70 × 8 = 144/560 - Likewise, for the 2nd fraction, since 80 × 7 = 560,
21/80 = 21 × 7/80 × 7 = 147/560 - Subtract the two like fractions:
144/560 - 147/560 = 144 - 147/560 = -3/560
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