Solutions by everydaycalculation.com

2190 - 121 is 1370.

- Find the least common denominator or LCM of the two denominators:

LCM of 90 and 21 is**630**

Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 90 × 7 = 630,

2190 = 21 × 790 × 7 = 147630 - Likewise, for the 2nd fraction, since 21 × 30 = 630,

121 = 1 × 3021 × 30 = 30630 - Subtract the two like fractions:

147630 - 30630 = 147 - 30630 = 117630 - After reducing the fraction, the answer is 1370

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