2/9 + 7/10 + -4/7 = ?
I got 221/630 but the answer in the back of the book shows 59/90... What am I doing wrong?
I got 221/630 but the answer in the back of the book shows 59/90... What am I doing wrong?
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Your answer is correct. The lowest common denominator for 9, 10 and 7 is 630. You need to multiply each fraction by a number to raise the denominator to 630:
70*(2/9) + 63*(7/10) - 90*(4/7) = ?
Which gets you:
140/630 + 441/630 - 360/630 = 221/630
Even if you look at it in decimal form:
.2222 + .7 - .5714 = .3508
59/90 = .6556
The answer in the back of your book is incorrect for the problem you posted.
70*(2/9) + 63*(7/10) - 90*(4/7) = ?
Which gets you:
140/630 + 441/630 - 360/630 = 221/630
Even if you look at it in decimal form:
.2222 + .7 - .5714 = .3508
59/90 = .6556
The answer in the back of your book is incorrect for the problem you posted.
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221/630