# Add / Subtract Rational Numbers: Unlike Fractions.

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Add / Subtract Rational Numbers: Unlike Fractions

51 4 += 1. Write horizontally 2. Determine common denominator * Count by largest denominator until the smallest denominator goes into it evenly 7 no 7 14 no 21 no 28 yes 207 28 += 3. Make equivalent fraction with new denominator Ask yourself What can I multiply the denominator by to get the needed denominator x4 Multiply the numerator by the same number x4 Repeat for the other fraction x7 4. Add numerator keep denominator 27 28 5. Simplify if necessary EX 1)

111 56 -= 4 x14 x1 1411 56 -= 3 x14 -3-11 12 += 4 x3 x1 x3 -9-11 12 += -20 12 -5 3 = 2 3 = EX 2) EX 3)

-31 4 += 4 -2 4 EX 4) -7513 52 = 100 Try simplifying your fractions first to make your problem easier = +

Notes start here

+= 1. Write ____________ 2. Determine ______ ___________ * Count by largest denominator until the smallest denominator goes into it evenly += 3. Make __________ ________ with new denominator Ask yourself What can I multiply the denominator by to get the needed denominator Multiply the numerator by the same number Repeat for the other fraction 4. ___ numerator ____ denominator 5. _________ if necessary EX 1)

+= += += += = = EX 2) EX 3)

+= EX 4) = Try __________ your _________ first to make your problem easier = +