M3L4 application problem.

Question

Leslie has 1 liter of milk in her refrigerator to drink today. She drank 1/2 liter of milk for breakfast and 2/5 liter of milk for dinner. How much of a liter did Leslie drink during breakfast and dinner? 

Extension: How much of a liter of milk does Leslie have left to drink with her dessert? Give your answer as a fraction of liters and as a decimal.

Answer 1

To add these two fractions, we first need a common denominator. In this case, that would be 10.

To convert the 1/2, we multiply both the numerator and denominator by 5, which gives us 5/10

To convert the 2/5, we multiply both the numerator and denominator by 2, which gives us 4/10

Our next step is to add these two fractions. 5/10 + 4/10 = 9/10

We know that Leslie drank 9/10 of a liter.

Extension:

To find how much of the liter Leslie has left, we have to subtract the amount that she drank from the amount that she started with. 1 liter is equal to 10/10 of a liter, so we can set up the expression 10/10 - 9/10, which we can solve to find the answer 1/10, meaning that she has 1/10 of a liter remaining. To put this in decimal form, we divide 1 by 10, which gives us 0.1 liters.