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&. dding. ubtracting. ractions. Objectives. Students will be able to: Identify highest common factors and least common multiples. Solve problems that involve adding and subtracting fractions with unlike denominators. Solve real world problems involving operations with fractions.
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& dding ubtracting ractions
Objectives • Students will be able to: • Identify highest common factors and least common multiples. • Solve problems that involve adding and subtracting fractions with unlike denominators. • Solve real world problems involving operations with fractions
We need a common denominator to add these fractions. +
We need a common denominator to add these fractions. + Count by 2's 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 Count by 7's 7, 14, 21, 28, 35…
Count by 2's 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 Count by 7's 7, 14, 21, 28, 35… The first number IN COMMON that appears on both lists becomes the common denominator
x 7 7 Make equivalent fractions. = X 7 x 2 6 Add the numerators = + 7 + 6 = 13 x 2 13
We need a common denominator to add these fractions. + Count by 7's 7, 14, 21, 28, 35, 42, 49, 56, 63 Count by 5's 5, 10, 15, 20, 25, 30, 35, 40, 45
x 5 15 Make equivalent fractions. = X 5 x 7 7 + Add the numerators = x 7 15 + 7 = 22 22
We need a common denominator to add these fractions. + Count by 7's 7, 14, 21, 28, 35, 42, 49, 56, 63 Count by 8's 8, 16, 24, 32, 40, 48, 56, 64, 72
32 x 8 Make equivalent fractions. = x 8 21 Add the numerators x 7 + 32 + 21 = 53 = x 7 53
We need a common denominator to subtract a fraction from another. - Count by 5's 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 Count by 11's 11, 22, 33, 44, 55, 66, 77…
15 x 5 Make equivalent fractions. = x 5 11 x 11 Subtract. = 15 - 11 = 4 - x 11 4
We need a common denominator to subtract one fraction from another. - Count by 2's 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 … Count by 10's 10, 20, 30…
5 x 5 Make equivalent fractions. = x 5 3 x 1 Subtract. - = 5 – 3 = 2 x 1 2 Simplify!!!
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Video Time! • Check out these videos for more explanations on how to solve addition and subtracting fraction problems with uncommon denominators. • Adding Fractions with Unlike denominators • Subtracting Fractions with Unlike Denominators
Classwork • Try this interactive site that guides you through solving addition and subtraction problems with fractions: Interactive SiteNext, Try Clara’s Ice Cream Shop Game for more practice. Finally, try out this Action Fraction Game to help you practice. Homework Time!! Adding and Subtracting Fractions with Unlike Denominators HO