What this worksheet covers
Equivalent fractions name the same amount in different pieces. Each problem here gives one fraction and half of its partner, with the missing number either on top or underneath: 2/3 = ___/12, or 3/4 = 9/___. To solve it a student must see what the first denominator was multiplied by and do the same to the numerator, or the other way round. Both numbers always change by the same factor.
Who it is for
Third and fourth grade, with review in fifth. Common Core 4.NF.A.1 asks students to explain why a fraction is equivalent to another by multiplying the top and bottom by the same number, and 3.NF.A.3 introduces the idea with simple cases.
Finding the missing number in two equal fractions · grades 3 and 4
A worked example
2/3 = ___/12. The denominator went from 3 to 12, which is times 4, so the numerator goes from 2 to 8: 8/12. For 3/4 = 9/___, the numerator went from 3 to 9, which is times 3, so the denominator goes from 4 to 12.
Mistakes to watch for
- Adding the same number to the top and bottom instead of multiplying, so 2/3 = 4/5. Compare the two fractions with a strip to show they are different.
- Changing only the denominator and leaving the numerator alone. Remind students that what happens to one happens to the other.
Make it your own
This sheet is one setting of the math worksheet generator. Open it there to change the skill, the range of numbers or the heading, or to mix several skills on one sheet.