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Help adding fractions
- Thread starter lydia
- Start date
Two steps9/20 + (-1/5) I dont know how to do this---please can someone tell me procedure
\(\displaystyle \dfrac{a}{b} + \dfrac{c}{d} = \dfrac{ad + bc}{bd}.\) You probably learned this in 3rd or 4th grade.
\(\displaystyle e + (- f) = e - f.\) You probably learned this in 7th or 8th grade.
For some reason, students have trouble with fractions. They are just numbers. Do NOT let them spook you. Negative numbers are just numbers. Do NOT let them spook you. And negative fractions are just numbers. Do NOT let them spook you either.
HallsofIvy
Elite Member
- Joined
- Jan 27, 2012
- Messages
- 7,763
You need a common denominator. In this case, 20= 4(5) so you can get "20" as common denominator by multiplying numerator and denominator of the second fraction by 4: \(\displaystyle \frac{9}{20}- \frac{1}{5}= \frac{9}{20}- \frac{4}{20}= \frac{9- 4}{20}= \frac{5}{20}\).9/20 + (-1/5) I dont know how to do this---please can someone tell me procedure
And, of course, because 20= 5(4) you can reduce that fraction: \(\displaystyle \frac{5}{20}= \frac{5}{(5)(4)}= \frac{1}{4}\).