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Multiplying Mixed Numbers - YourTeacher.com - Pre Algebra Help
By yourteachermathhelp
For a complete lesson on multiplying mixed numbers go to http://www.yourteacher.com - 1000+ online math lessons featuring a personal math teacher inside every lesson! In this lesson students learn to multiply mixed numbers by first rewriting the mixed numbers as improper fractions then multiplying the improper fractions together then rewriting the resulting improper fraction as a mixed number if necessary. For example to multiply 1 8/15 x 1 1/4 first rewrite the mixed numbers as improper fractions to get 23/15 x 5/4. Next cross-cancel the 15 and 5 to 3 and 1 and we have 23/3 x 1/4. Next multiply across the numerators and denominators to get 23/12. Finally rewrite 23/12 as the mixed number 1 11/12.
Adding Mixed Numbers - YourTeacher.com - Pre Algebra Help
By yourteachermathhelp
For a complete lesson on adding mixed numbers go to http://www.yourteacher.com - 1000+ online math lessons featuring a personal math teacher inside every lesson! In this lesson students learn to add mixed numbers by first adding the fractions then adding the whole numbers. For example to add 4 2/5 + 7 4/5 first add 2/5 + 4/5 to get 6/5 then add 4 + 7 to get 11. So 4 2/5 + 7 4/5 = 11 6/5. Notice however that the answer 11 6/5 contains an improper fraction 6/5 which is the same as 1 1/5 so 11 6/5 can be rewritten as 11 + 1 1/5 which simplifies to 12 1/5. So 4 2/5 + 7 4/5 = 12 1/5. Note that some of the problems in this lesson also require the student to find a common denominator for the fractions. For example 5 1/4 + 6 3/8.
Perimeter Word Problems | MathHelp.com
By MathHelp.com
This lesson covers the area of a trapezoid. Students learn that a trapezoid is a quadrilateral with one pair of parallel sides, and the formula for the area of a trapezoid is 1/2 times (base 1 + base 2) times height. For example, the area of a trapezoid that has bases of 10 centimeters and 12 centimeters and a height of 8 centimeters is 1/2 times (10 + 12) times 8, which simplifies to 1/2 times 22 times 8, or 11 times 8, which is 88 square centimeters.
