Question

What is the sum of the fractions? Use the number line and equivalent fractions to help find the answer.

Answer 1

Answer:  -3/4  (choice C)

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Explanation:

Think of a whole cake or pizza. Now slice it into 4 equal pieces. This represents 1 is the same as 4/4.

Adding on another quarter slice gets us 4/4+1/4 = 5/4

In other words, the mixed number 1 & 1/4 is the same as the improper fraction 5/4.

So 1 & 1/4 = 5/4

This then means -1 & 1/4 = -5/4 because we multiply both sides by -1.

Now we'll add on 1/2, which is the same as 2/4, like so

(-1 & 1/4) + 1/2

-(1 & 1/4) + 2/4

-(1 + 1/4) + 2/4

-1 - 1/4 + 2/4

-1 + (-1/4 + 2/4)

-1 + 1/4

-4/4 + 1/4

-3/4

which points us to choice C as our final answer

Notice how if we started at -5/4, and moved to the right 2 tickmarks, we arrive at -3/4. Each tickmark represents 1/4 of a unit, so two of them is 2/4 = 1/2.

Side note: -3/4 converts to the decimal -0.75