Subtract 21/80 from 4/90
4/90 - 21/80 is -157/720.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 80 is 720
Next, find the equivalent fraction of both fractional numbers with denominator 720 - For the 1st fraction, since 90 × 8 = 720,
4/90 = 4 × 8/90 × 8 = 32/720 - Likewise, for the 2nd fraction, since 80 × 9 = 720,
21/80 = 21 × 9/80 × 9 = 189/720 - Subtract the two like fractions:
32/720 - 189/720 = 32 - 189/720 = -157/720
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