Which fraction equals 3 4 \frac{3}{4} ?
Fold equal strips into halves and quarters. Compare one half with two quarters.
Shade one of two equal parts. Divide every part into two again: the shaded area now covers two of four parts. The amount has not changed. Multiplying both numerator and denominator by the same positive whole number renames the fraction: 1 2 = 2 4 = 3 6 \frac{1}{2} = \frac{2}{4} = \frac{3}{6} . Multiplying only the top changes the amount.
1.
Complete 1 3 = ? 6 \frac{1}{3} = \frac{?}{6} and draw equal wholes to check. 2.
Complete 3 5 = ? 10 \frac{3}{5} = \frac{?}{10} . Name the multiplier. 3.
Are 4 6 \frac{4}{6} and 2 3 \frac{2}{3} equivalent? Explain using division. 4.
Sam says 2 5 = 4 7 \frac{2}{5} = \frac{4}{7} because both numbers went up by two. Explain the error with a correct equivalent fraction. What number completes 2 5 = ? 15 \frac{2}{5} = \frac{?}{15} ?
Samโs fraction repair and why adding two fails
Which change preserves the value of 4 7 \frac{4}{7} ?
A
Multiply top and bottom by 3
B
Add 3 to the top
C
Multiply only the bottom by 3
1.
2 6 \frac{2}{6} : split each third into two, so both numbers double. 2.
6 10 \frac{6}{10} : multiply numerator and denominator by 2. 3.
Yes: divide both 4 and 6 by 2 to get 2 3 \frac{2}{3} . 4.
Adding the same amount does not preserve the ratio. Doubling gives 4 10 \frac{4}{10} , not 4 7 \frac{4}{7} . ๐ก Hint and challenge # ๐ก Hint: Keep the paper strips aligned and count shaded parts before writing symbols.
โญ Challenge: Find two fractions equivalent to 3 5 \frac{3}{5} with denominators above 20; explain the multiplier.
15 25 \frac{15}{25} and 18 30 \frac{18}{30} both equal 3 5 \frac{3}{5} : multiply both numbers by 5 or by 6. Both denominators exceed 20.
Statistics investigation using a supplied dataset .