Q1. If the ratio is 3 : 2, what fraction represents the first part?
✔ Add parts 3 + 2 = 5. First part is 3 over total 5.
Q2. Wei Ming and Mei Ling share ten dollars in ratio 1 : 4. How much does Mei Ling get?
✔ Mei Ling gets 4/5 of ten dollars, which equals eight dollars.
Q3. For a ratio of 2 : 3, what is the correct denominator for the fractions?
✔ The denominator is the total shares, so add 2 plus 3 to get 5.
Show transcript
[Slide 1] Understanding Ratio Parts
Welcome back, class! Today we link ratios to fractions using real Singapore examples. Imagine Ravi and Siti splitting lunch money at the hawker centre.
[Slide 2] The Conversion Rule
To find fractions, add the ratio numbers together first. Then place each number over this total sum. This gives you the share of the whole.
[Slide 3] Worked Example Setup
Let's say Ravi and Siti share five dollars in the ratio two to three. We draw two bars for Ravi and three bars for Siti. The total number of parts is five.
[Slide 4] Worked Example Solution
Siti's fraction is three over five because she has three parts. Multiply this by the total amount to find her share. She receives three dollars for her meal.
[Slide 5] Common Mistake Alert
A common error is using the second number as the denominator directly. Remember, the bottom number must be the total shares. Your fractions must always add up to one.
[Slide 6] Quick Recap
To recap, turn ratio parts into fractions by adding them first. Use the bar model to visualise the shares clearly. Now you can solve PSLE questions confidently!