AI generatedRatio, proportion and rates of changeKey Stage 3

Converting a part-to-part ratio into fractions

A part-to-part ratio compares the categories with each other.

  • A part-to-part ratio compares the categories with each other.
  • Add the ratio parts to get the denominator for a fraction of the whole.
  • Each category contributes its own ratio number to the numerator.

Example 1

Red : blue = 2 : 3. What fraction of all the counters is red?

Add the parts to get the whole.Red parts go above total parts.

Example 2

Red : blue = 3 : 4. What fraction of all the counters is red?

Add the parts to get the whole.Red parts go above total parts.

Remember
Use the worked steps to check your method, not just the final answer.

Your turn

Question 1

Red : blue = 4 : 5. What fraction of all the counters is red?

Check answer
Add the parts to get the whole.Red parts go above total parts.
Question 2

Red : blue = 5 : 6. What fraction of all the counters is red?

Check answer
Add the parts to get the whole.Red parts go above total parts.
Question 3

Red : blue = 6 : 7. What fraction of all the counters is red?

Check answer
Add the parts to get the whole.Red parts go above total parts.
Question 4

Red : blue = 7 : 8. What fraction of all the counters is red?

Check answer
Add the parts to get the whole.Red parts go above total parts.
Question 5

Red : blue = 8 : 9. What fraction of all the counters is red?

Check answer
Add the parts to get the whole.Red parts go above total parts.
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