Subtract 1/45 from 42/21, Solve 2 0/21

Subtract 1/45 from 42/21

1^st number: 2 0/21, 2^nd number: 1/45

42/21 - 1/45 is 89/45.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 45 is 315

Next, find the equivalent fraction of both fractional numbers with denominator 315
For the 1st fraction, since 21 × 15 = 315,
42/21 = 42 × 15/21 × 15 = 630/315
Likewise, for the 2nd fraction, since 45 × 7 = 315,
1/45 = 1 × 7/45 × 7 = 7/315
Subtract the two like fractions:
630/315 - 7/315 = 630 - 7/315 = 623/315
After reducing the fraction, the answer is 89/45
In mixed form: 144/45

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