Worked examples
Two examples
Example 1
12 + 13 =
- Rewrite with the common denominator 6: 36 + 26.
- Add the numerators: 3 + 2 = 5.
Answer: 56
Example 2
34 − 16 =
- Rewrite with 12: 912 − 212.
- Subtract the numerators: 9 − 2 = 7.
Answer: 712
Where this is taught: Quiz 10: Adding and Subtracting Fractions, “Different sizes: re-cut until they match”
The drill
Ten problems
How many:
Type a fraction with a slash, like 3/4, and a mixed number with a space, like 2 1/4. Give answers in simplest form. Then press Check my answers at the bottom.Write each answer on the line, in simplest form. The answer key, with the reasoning, is on the last page.