66 Part 1: The World of Numbers
For subtraction, it can be trickier, because there may be regrouping, or borrowing, involved. Try
to subtract the fraction parts, and if you can, then you can also just subtract the whole numbers.If you try subtracting the fractions and realize the first fraction is smaller than the second, you
need to borrow from the first whole number. To subtract 8
1
5 24
5(^2) , you need to borrow 1 from
the 8.
854 22 22 215 55 5 (^811542151825415635)
81
5
24
5
711
5
24
5
7 5
5
1
5
24
5
76
5
24
5
52
5
2511255511 2 2
CHECK POINT
Complete each addition or subtraction problem.
16.^47135
17.^89214
18. 1521318
- (^7231934)
- (^51012112)
The Least You Need to Know
- To change a fraction to an equivalent form, multiply (or divide) both the num erator
and the denominator by the same number. - To multiply fractions, multiply the numerators, multiply the denominators, and
simplify if possible. You may be able to simplify before multiplying by dividing a
numerator and a denominator by the same number. - To divide fractions, invert the divisor and multiply.
- The lowest common denominator of two fractions is the LCM of the two
denominators. - To add or subtract fractions, change each fraction to an equivalent fraction with a
common denominator, and add or subtract the numerators. Simplify if possible.