Subtract Fractions 71A6Bf

1. **State the problem:** We need to subtract each pair of fractions and find the answers. 2. **Formula for subtracting fractions:** $$\frac{a}{b} - \frac{c}{d} = \frac{ad - bc}{bd}$$ 3. **Important rule:** To subtract fractions, find a common denominator, then subtract the numerators. 4. **Solve each problem step-by-step:** **(a) $\frac{3}{8} - \frac{1}{4}$** - Common denominator is 8. - Rewrite $\frac{1}{4} = \frac{2}{8}$. - Subtract: $\frac{3}{8} - \frac{2}{8} = \frac{3-2}{8} = \frac{1}{8}$. **(b) $\frac{5}{12} - \frac{2}{6}$** - Common denominator is 12. - Rewrite $\frac{2}{6} = \frac{4}{12}$. - Subtract: $\frac{5}{12} - \frac{4}{12} = \frac{5-4}{12} = \frac{1}{12}$. **(c) $\frac{8}{9} - \frac{2}{3}$** - Common denominator is 9. - Rewrite $\frac{2}{3} = \frac{6}{9}$. - Subtract: $\frac{8}{9} - \frac{6}{9} = \frac{8-6}{9} = \frac{2}{9}$. **(d) $\frac{5}{10} - \frac{1}{5}$** - Common denominator is 10. - Rewrite $\frac{1}{5} = \frac{2}{10}$. - Subtract: $\frac{5}{10} - \frac{2}{10} = \frac{5-2}{10} = \frac{3}{10}$. **(e) $\frac{2}{3} - \frac{1}{9}$** - Common denominator is 9. - Rewrite $\frac{2}{3} = \frac{6}{9}$. - Subtract: $\frac{6}{9} - \frac{1}{9} = \frac{6-1}{9} = \frac{5}{9}$. **(f) $\frac{2}{5} - \frac{3}{10}$** - Common denominator is 10. - Rewrite $\frac{2}{5} = \frac{4}{10}$. - Subtract: $\frac{4}{10} - \frac{3}{10} = \frac{4-3}{10} = \frac{1}{10}$. **(g) $\frac{11}{12} - \frac{2}{4}$** - Common denominator is 12. - Rewrite $\frac{2}{4} = \frac{6}{12}$. - Subtract: $\frac{11}{12} - \frac{6}{12} = \frac{11-6}{12} = \frac{5}{12}$. **(h) $\frac{9}{10} - \frac{1}{5}$** - Common denominator is 10. - Rewrite $\frac{1}{5} = \frac{2}{10}$. - Subtract: $\frac{9}{10} - \frac{2}{10} = \frac{9-2}{10} = \frac{7}{10}$. **(i) $\frac{11}{12} - \frac{1}{3}$** - Common denominator is 12. - Rewrite $\frac{1}{3} = \frac{4}{12}$. - Subtract: $\frac{11}{12} - \frac{4}{12} = \frac{11-4}{12} = \frac{7}{12}$. **(j) $\frac{7}{8} - \frac{1}{4}$** - Common denominator is 8. - Rewrite $\frac{1}{4} = \frac{2}{8}$. - Subtract: $\frac{7}{8} - \frac{2}{8} = \frac{7-2}{8} = \frac{5}{8}$. **(k) $\frac{9}{15} - \frac{2}{5}$** - Common denominator is 15. - Rewrite $\frac{2}{5} = \frac{6}{15}$. - Subtract: $\frac{9}{15} - \frac{6}{15} = \frac{9-6}{15} = \frac{3}{15}$. - Simplify $\frac{3}{15} = \frac{\cancel{3}^1}{\cancel{15}^5} = \frac{1}{5}$. **(l) $\frac{8}{15} - \frac{2}{5}$** - Common denominator is 15. - Rewrite $\frac{2}{5} = \frac{6}{15}$. - Subtract: $\frac{8}{15} - \frac{6}{15} = \frac{8-6}{15} = \frac{2}{15}$. 5. **Final answers:** - (a) $\frac{1}{8}$ - (b) $\frac{1}{12}$ - (c) $\frac{2}{9}$ - (d) $\frac{3}{10}$ - (e) $\frac{5}{9}$ - (f) $\frac{1}{10}$ - (g) $\frac{5}{12}$ - (h) $\frac{7}{10}$ - (i) $\frac{7}{12}$ - (j) $\frac{5}{8}$ - (k) $\frac{1}{5}$ - (l) $\frac{2}{15}$ 6. **Riddle answer:** The fractions correspond to letters (not provided here), but the question is "Why did Mickey Mouse become an astronaut?" The common joke answer is "To visit Pluto!"