Question

1/2 + 2/5 pls help me I’m struggling

Answer 1

Answer:

  9/10

Step-by-step explanation:

If you are truly "struggling," you might want to consider working the problem using your calculator. It will give you a decimal answer: 0.9.

You know this is nine tenths, or 9/10 when written as a fraction.

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When adding fractions, you are instructed to use a common denominator. Usually, that instruction is to find the "least" common denominator. In many cases, that simplifies reducing the fraction that will be the answer.

However, any common denominator will do. The easiest one to find is the product of the denominators. Here, that is 2·5 = 10.

The first fraction has a denominator of 2, so to make its denominator 10, you need to multiply it by 5/5.

The second fraction has a denominator of 5, so to make its denominator 10, you need to multiply it by 2/2.

  $\dfrac{1}{2}+\dfrac{2}{5}\\\\=\dfrac{1(5)}{2(5)}+\dfrac{2(2)}{5(2)}=\dfrac{5}{10}+\dfrac{4}{10}=\dfrac{5+4}{10}\\\\=\boxed{\dfrac{9}{10}}$

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Effectively, we have used the formula for the sum of two fractions:

  (a/b) +(c/d) = (ad +bc)/(bd)

  1/2 + 2/5 = (1·5 +2·2)/(2·5) = 9/10