AR · 8 cards

Fractions and Mixed Numbers flashcards

8 cards with the formulas, rules and traps from this lesson. Answer in your head, then flip to check.

Term · 1/8
In a fraction, what do the numerator and denominator tell you?
The denominator (bottom) is how many equal parts make the whole; the numerator (top) is how many parts are counted. A fraction is also a division: $\frac{3}{4} = 3 \div 4 = 0.75$ .
Rule · 2/8
How do you put a fraction in simplest form?
Divide the top and bottom by their greatest common factor: $\frac{12}{30} = \frac{12 \div 6}{30 \div 6} = \frac{2}{5}$ .
Strategy · 3/8
How can you tell which is larger, $\frac{4}{7}$ or $\frac{5}{9}$ ?
Cross-multiply: $4 \times 9 = 36$ and $5 \times 7 = 35$ . The larger product goes with $\frac{4}{7}$ , so $\frac{4}{7}$ is larger.
Rule · 4/8
How do you change a mixed number to an improper fraction?
Multiply the whole number by the denominator, add the numerator, and keep the denominator: $4 \frac{3}{8} = \frac{4 \times 8 + 3}{8} = \frac{35}{8}$ .
Common trap · 5/8
Why is $\frac{1}{3} + \frac{1}{4}$ not $\frac{2}{7}$ ?
Denominators are never added. Rename both with a common denominator, then add numerators: $\frac{4}{12} + \frac{3}{12} = \frac{7}{12}$ .
Rule · 6/8
How do you multiply fractions?
Multiply numerators together and denominators together; no common denominator is needed. Cancel shared factors first: $\frac{4}{9} \times \frac{15}{16} = \frac{5}{12}$ .
Rule · 7/8
How do you divide by a fraction?
Keep the first fraction, change division to multiplication, and flip only the divisor: $\frac{5}{6} \div \frac{2}{3} = \frac{5}{6} \times \frac{3}{2} = \frac{5}{4} = 1 \frac{1}{4}$ .
Common trap · 8/8
Can you multiply mixed numbers whole part by whole part?
No. Convert to improper fractions first: $2 \frac{1}{2} \times 3 \frac{1}{3} = \frac{5}{2} \times \frac{10}{3} = \frac{25}{3} = 8 \frac{1}{3}$ , not $6 \frac{1}{6}$ .

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