Question

Teresa needs

1
1
-
2
cups of flour to make pancakes and
2
1
-
3
cups of flour for a cake. What is the total amount of flour that Teresa needs?

Answer 1

3 5/6 cups of flour

Explanation:

You want the total amount so we add both fractions together.

1 1/2 + 2 1/3

I prefer to convert both to an improper fraction and then convert back to a mixed number, so;

1 1/2 = whole number (1) x denominator (2), add numerator (1), = 3, put this over the old denominator (2) = 3/2

2 1/3 = whole number (2) x denominator (3), add numerator (1), = 7, put this over the old denominator (3) = 7/3

Now we add the 2 improper fractions, so we have to convert them both to a common denominator. The LCM of 2 and 3 is 6, so it will be over 6.

3/2 = to get from 2 to 6, you multiply by 3, numerator (3) x 3 = 9, over 6 = 9/6.

7/3 = to get from 3 to 6, you multiply by 2, numerator (7) x 2 = 14, over 6 = 14/6.

9/6 + 14/6 = 23/6

Now we change back into a mixed number, how many times do 6 go into 23? 3 (6x3=18), as 4 would be 24.

So our whole number is 3

What is left goes over our denominator (6): 23 - 18 = 5.

So your answer is 3 5/6 cups of flour.