Transcript Fractions & Decimals

FRACTIONS & DECIMALS
How to add , subtract , multiply , & divide
fractions and decimals.
FRACTIONS : ADDITION
1.Rewrite fractions with common denominators
a. If you have a mixed #, rewrite the whole # in front
of
the “new” fraction with the common denominator.
b. If you have a whole #, rewrite the whole number
and
write the fraction as 0 over the denominator of the
fraction.
7/12 + 3/4 = 7/12 + 9/12 = 16/12=1 1/3
2. Denominators stay the same
3.Add numerators
4.Add whole #’s
5.Simplify
a. Rewrite improper fractions as mixed numbers
b. Divide by common factors to simplify fraction
s
FRACTIONS: SUBTRACTION
1.Rewrite fractions with common denominators
a. If you have a mixed #, rewrite the whole # in front of
the “new” fraction with the common denominator.
b. If you have a whole #, rewrite the whole number and
write the fraction as 0 over the denominator of the
fraction.
2. Denominators stay the same
3/8
-
1/4 = 3/8 – 2/8 = 1/8
FRACTIONS: MULTIPLICATION
1.
Change mixed numbers to improper fractions
a. Multiply the whole number by the denominator
b. Add that to the numerator
2.Cancel out
2 3/4 x 5/8=
11/4 x 5/8= 55/32 = 1 23/32
3. Multiply the numerator times numerator
and the denominator times the denominator
4. Simplify
a. Rewrite improper fractions as mixed numbers
b. Divide by common factors to simplify fractions
FRACTIONS: DIVISION
1.
Change improper fractions to mixed numbers
2. Rewrite first number
3.Change the division to multiplication
4.Flip the numbers of the second fractions
5. Cancel out if possible
6.Multiply numerators (top #s)
7. Multiply denominators (bottom 3s)
8. Simplify
a. Rewrite improper fractions as mixed numbers
b. Divide by common factors to simplify fractions
1/4 divided by 3/5
1/4 x 5/3 = 5/12
DECIMALS : ADDITION
1.
2.
Line up decimals
Add
2.5
+ 8.0
10.5
DECIMALS: SUBTRACTION
1.
2.
3.
Line up decimals
Be careful with borrowing
Subtract
10.
-0.98
9.02
DECIMALS: MULTIPLICATION
1.
2.
3.
Don’t have to line up decimals
Multiply as if there is no decimals
Count the # of #’s behind the decimals in the
problem & put that many #’s behind the decimal in
the answer
5.1 -1
x .13 -2
153
+510
.663
DECIMALS : DIVISION
1.
2.
3.
Move decimal in divisor so that it is a whole #
Move the decimal in the dividend the same # of
times
Divide
.25
5.75 = 23
I GET IT!!!