David W. answered • 02/09/16
Tutor
4.7
(90)
Experienced Prof
You may think of mixed numbers like dollars and cents (which is easy) or hours and minutes (which is a little harder) or pounds and ounces (which is also a little harder). If you don't need to borrow, then the problem is easy.
What is:
10 pounds 15 ounces
- 5 pounds 4 ounces
--------------------------
5 pounds 11 ounces
Problem 1 (method 1 - standard subtraction):
11 1/3
- 6 11/12
----------------
10 4/3 [borrowed 1 = 3/3]
- 6 11/12
-----------------
10 16/12 [converted to common denominator]
- 6 11/12
-----------------
4 5/12
Problem 1 (method 2 - convert to improper fractions):
11 1/3 - 6 11/12
34/3 - 83/12 [convert mixed numbers to improper fractions]
136/12 - 83/12
(136 - 83)/12 [common denominator, so subtract]
53/12
4 5/12 [convert to mixed number]
The other problems are more of the same. You probably are using one or the other method. Common denominator and changing from mixed number to improper fraction and back are important.
