Fraction Fusion Solutions • Grade 6-8 Pre-Algebra / Algebra 1 Page 1 of 3
Fraction Fusion Solutions | Part II: Division & Complex Fractions
Scaffolded Key
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Multiply by Reciprocal
Problem 7 \(\frac{7}{10} \div \frac{14}{15}\)
• Reciprocal: \(\frac{7}{10} \times \frac{15}{14}\)
• Cancel 7 & 14: \(\to 1\) & \(2\); Cancel 10 & 15: \(\to 2\) & \(3\)
• Multiply: \(\frac{1 \times 3}{2 \times 2} = \frac{3}{4}\)
Answer: \(\frac{3}{4}\)
Problem 8 \(3\frac{1}{3} \div \frac{5}{6}\)
• Convert: \(3\frac{1}{3} = \frac{10}{3}\) → \(\frac{10}{3} \times \frac{6}{5}\)
• Cancel 10 & 5: \(\to 2\) & \(1\); Cancel 6 & 3: \(\to 2\) & \(1\)
• Multiply: \(\frac{2 \times 2}{1 \times 1} = 4\)
Answer: \(4\)
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Multi-Method Breakdown
Problem 9: \(\frac{\frac{3}{4}}{\frac{9}{16}}\)
Method 1 (Division Sign):
\(\frac{3}{4} \div \frac{9}{16} = \frac{3}{4} \times \frac{16}{9} = \frac{1 \times 4}{1 \times 3} = \frac{4}{3} = 1\frac{1}{3}\)
Method 2 (Clear by LCD 16):
\(\frac{\frac{3}{4} \times 16}{\frac{9}{16} \times 16} = \frac{12}{9} = \frac{4}{3} = 1\frac{1}{3}\)
Answer: \(\frac{4}{3}\) or \(1\frac{1}{3}\)
Problem 10: \(\frac{\frac{4}{5} - \frac{1}{2}}{\frac{3}{10}}\)
Step 1: Simplify Numerator:
\(\frac{4}{5} - \frac{1}{2} = \frac{8}{10} - \frac{5}{10} = \frac{3}{10}\)
Step 2: Divide by Denominator:
\(\frac{\frac{3}{10}}{\frac{3}{10}} = \frac{3}{10} \times \frac{10}{3} = 1\)
Answer: \(1\)
Problem 11: \(\frac{\frac{1}{3} + \frac{1}{2}}{\frac{5}{8}}\)
Step 1: Simplify Numerator:
\(\frac{1}{3} + \frac{1}{2} = \frac{2}{6} + \frac{3}{6} = \frac{5}{6}\)
Step 2: Multiply by Reciprocal:
\(\frac{5}{6} \div \frac{5}{8} = \frac{5}{6} \times \frac{8}{5} = \frac{1 \times 4}{3 \times 1} = \frac{4}{3} = 1\frac{1}{3}\)
Answer: \(\frac{4}{3}\) or \(1\frac{1}{3}\)
Problem 12: \(\frac{1 - \frac{1}{4}}{\frac{3}{8} + \frac{1}{2}}\)
Step 1: Numerator: \(1 - \frac{1}{4} = \frac{3}{4}\)
Step 2: Denominator: \(\frac{3}{8} + \frac{4}{8} = \frac{7}{8}\)
Step 3: Invert & Multiply:
\(\frac{3}{4} \times \frac{8}{7} = \frac{3 \times 2}{1 \times 7} = \frac{6}{7}\)
Answer: \(\frac{6}{7}\)
Pedagogical Tip for Complex Fractions:
Students struggling with multi-step complex fractions often try to flip terms prematurely. Emphasize that the numerator and denominator must each be condensed into a single fraction before applying "Keep, Change, Flip", OR students can multiply the entire numerator and denominator by the overall LCD (\(\text{LCD of } 4, 8, 2 = 8\) in Problem 12: \(\frac{8 - 2}{3 + 4} = \frac{6}{7}\)).
Fraction Fusion Solutions • Grade 6-8 Pre-Algebra / Algebra 1 Page 2 of 3
Part III Solutions Independent Mastery Key
Full Solutions 12 Independent Items
Prob 13: \(\frac{5}{9} + \frac{7}{12}\)
LCD = 36
\(\frac{20}{36} + \frac{21}{36} = \frac{41}{36}\)
\(\frac{41}{36}\) or \(1\frac{5}{36}\)
Prob 14: \(\frac{11}{15} - \frac{3}{10}\)
LCD = 30
\(\frac{22}{30} - \frac{9}{30} = \frac{13}{30}\)
\(\frac{13}{30}\)
Prob 15: \(3\frac{1}{6} - 1\frac{4}{9}\)
\(\frac{19}{6} - \frac{13}{9} = \frac{57 - 26}{18}\)
\(= \frac{31}{18}\)
\(\frac{31}{18}\) or \(1\frac{13}{18}\)
Prob 16: \(\frac{1}{2} - \frac{1}{3} + \frac{3}{4}\)
LCD = 12
\(\frac{6 - 4 + 9}{12} = \frac{11}{12}\)
\(\frac{11}{12}\)
Prob 17: \(\frac{9}{14} \times \frac{21}{27}\)
\(\frac{9}{27} \to \frac{1}{3}\); \(\frac{21}{14} \to \frac{3}{2}\)
\(\frac{1 \times 3}{2 \times 3} = \frac{1}{2}\)
\(\frac{1}{2}\)
Prob 18: \(2\frac{2}{3} \times 1\frac{7}{8}\)
\(\frac{8}{3} \times \frac{15}{8}\)
Cancel 8s; \(\frac{15}{3} = 5\)
\(5\)
Prob 19: \(\frac{8}{15} \div \frac{12}{25}\)
\(\frac{8}{15} \times \frac{25}{12} = \frac{2 \times 5}{3 \times 3}\)
\(= \frac{10}{9}\)
\(\frac{10}{9}\) or \(1\frac{1}{9}\)
Prob 20: \(4\frac{1}{2} \div 3\frac{3}{8}\)
\(\frac{9}{2} \times \frac{8}{27} = \frac{1 \times 4}{1 \times 3}\)
\(= \frac{4}{3}\)
\(\frac{4}{3}\) or \(1\frac{1}{3}\)
Problem 21: \(\frac{\frac{5}{18}}{\frac{10}{27}}\)
• Rewrite: \(\frac{5}{18} \div \frac{10}{27} = \frac{5}{18} \times \frac{27}{10}\)
• Cancel 5 & 10 \(\to 1\) & \(2\); Cancel 27 & 18 by 9 \(\to 3\) & \(2\)
• Multiply: \(\frac{1 \times 3}{2 \times 2} = \frac{3}{4}\)
Answer: \(\frac{3}{4}\)
Problem 22: \(\frac{\frac{5}{6} - \frac{1}{4}}{\frac{7}{12}}\)
• Numerator: \(\frac{10}{12} - \frac{3}{12} = \frac{7}{12}\)
• Divide: \(\frac{7}{12} \div \frac{7}{12} = \frac{7}{12} \times \frac{12}{7} = 1\)
• Alternate: Multiply top & bottom by 12: \(\frac{10 - 3}{7} = \frac{7}{7} = 1\)
Answer: \(1\)
Problem 23: \(\frac{\frac{2}{5} + \frac{3}{10}}{1 - \frac{1}{6}}\)
• Numerator: \(\frac{4}{10} + \frac{3}{10} = \frac{7}{10}\)
• Denominator: \(\frac{6}{6} - \frac{1}{6} = \frac{5}{6}\)
• Divide: \(\frac{7}{10} \times \frac{6}{5} = \frac{7 \times 3}{5 \times 5} = \frac{21}{25}\)
Answer: \(\frac{21}{25}\)
Problem 24: \(\frac{\frac{3}{4} + \frac{2}{3}}{\frac{5}{6} - \frac{1}{8}}\)
• Numerator: \(\frac{9 + 8}{12} = \frac{17}{12}\)
• Denominator: \(\frac{20 - 3}{24} = \frac{17}{24}\)
• Divide: \(\frac{17}{12} \times \frac{24}{17} = \frac{24}{12} = 2\)
Answer: \(2\)
Fraction Fusion Solutions • Grade 6-8 Pre-Algebra / Algebra 1 Page 3 of 3