Add/Subtract Fractions
(*HINT* you should have 4 steps!)
Find a common denominator.
Add or subtract NUMERATOR.
DENOMINATOR stays the same!
Simplify if needed
How do you multiply fractions?
Multiply across!
Numerator X numerator
Denominator X denominator
Simplify if needed
How do you divide fractions?
Keep, Change, Flip
Keep first fraction the same
Change from division to multiplication
Flip second fraction
How do you add or subtract decimals?
Line up the decimal points
Add or subtract
Decimal point drops straight down into the answer
How do you multiply decimals?
Multiply as "usual"
Count numbers behind decimal point in original, decimal point goes that many places in in the answer
Subtract!
3/4 - 1/4
1/2
Multiply
1/3 xx 4/5
4/15
Divide! *remember to simplify!*
2/3 div 1/3
2
Add!
2.3 + 1.4
3.7
Multiply!
32.445 xx 1
32.445
Add!
1/2 + 1/2
1
Multiply! *remember to simplify*
2/3 xx 1/6
1/9
Divide!
2/5 div 1/2
4/5
Subtract
5.7 - 2.1
4.6
Multiply!
2.5 xx 3.7
9.25
Subtract! *remember to simplify!*
2 1/6 - 1/3
1 5/6
Multiply! *remember to simplify!*
1 1/2 xx 2/3
2
Add!
8.234 + 9.12
17.354
Multiply!
5.21 xx 4.2
21.882
Add! *remember to simplify!*
3 3/4 + 1 1/8
4 7/8
Multiply! *remember to simplify!*
2 1/2 xx 1 2/3
4 1/6
Subtract!
10.76 - 4.2
6.56
Multiply!
7.23 xx 9.7
70.131