Subtract 18/72 from 90/70, Solve 1 20/70

Subtract 18/72 from 90/70

1^st number: 1 20/70, 2^nd number: 18/72

90/70 - 18/72 is 29/28.

Find the least common denominator or LCM of the two denominators:
LCM of 70 and 72 is 2520

Next, find the equivalent fraction of both fractional numbers with denominator 2520
For the 1st fraction, since 70 × 36 = 2520,
90/70 = 90 × 36/70 × 36 = 3240/2520
Likewise, for the 2nd fraction, since 72 × 35 = 2520,
18/72 = 18 × 35/72 × 35 = 630/2520
Subtract the two like fractions:
3240/2520 - 630/2520 = 3240 - 630/2520 = 2610/2520
After reducing the fraction, the answer is 29/28
In mixed form: 11/28

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