Subtract 72/90 from 45/70
45/70 - 72/90 is -11/70.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 70 × 9 = 630,
45/70 = 45 × 9/70 × 9 = 405/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
72/90 = 72 × 7/90 × 7 = 504/630 - Subtract the two like fractions:
405/630 - 504/630 = 405 - 504/630 = -99/630 - After reducing the fraction, the answer is -11/70
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Related: 90/70-72/90