Vocabulary
Least Common Denominator (LCD) - he smallest common multiple of the denominators of two or more fractions.
Mixed Numbers - A number with an integer part and fraction part.
Simplest Form - A fraction whose numerator and denominator have no common factor greater than 1.
Adding and Subtracting Mixed Fractions
  |
Quick Definition: A Mixed Fraction is a whole number and a fraction combined, such as 1 3 4 |
| 1 3/4 | |
| (one and three-quarters) |
 |
Quick Definition: An Improper fraction has a top number larger than or equal to the bottom number, such as 7 4 or 4 3 (It is "top-heavy") |
| 7/4 | |
| (seven-fourths or seven-quarters) |
Adding Mixed Fractions
I find this is the best way to add mixed fractions:- convert them to Improper Fractions
- then add them (using Addition of Fractions)
- then convert back to Mixed Fractions:
Example: What is 2 3 4 + 3 1 2 ?
Convert to Improper Fractions:
2
3
4
=
11
4
3
1
2
=
7
2
Common denominator of 4:
11
4
stays as
11
4
7
2
becomes
14
4
(by multiplying top and bottom by 2)
Now Add:(by multiplying top and bottom by 2)
11
4
+
14
4
=
25
4
Convert back to Mixed Fractions:
25
4
= 6
1
4
Example: What is 3 5 8 + 1 3 4
Convert them to improper fractions:
3
5
8
=
29
8
1 3 4 = 7 4
Make same denominator:
7
4
becomes
14
8
(by multiplying top and bottom by 2)1 3 4 = 7 4
And add:
29
8
+
14
8
=
43
8
= 5
3
8
Subtracting Mixed Fractions
Just follow the same method, but subtract instead of add:Example: What is 15 3 4 − 8 5 6 ?
Convert to Improper Fractions:
15
3
4
=
63
4
8
5
6
=
53
6
Common denominator of 12:
63
4
becomes
189
12
53
6
becomes
106
12
Now Subtract:
189
12
−
106
12
=
83
12
Convert back to Mixed Fractions:
83
12
= 6
11
12
VIDEO HELP
https://www.khanacademy.org/math/pre-algebra/fractions-pre-alg/mixed-number-add-sub-pre-alg/v/adding-subtracting-mixed-numbers-1-ex-1
https://www.youtube.com/watch?v=J8kjXfD4xas
https://www.youtube.com/watch?v=KW4XN0fs1K8
No comments:
Post a Comment