← Singapore Primary 6 (PSLE, age 12) Mathematics ยท Fractions

Dividing a whole number by a proper fraction

Practice Quiz

Q1. Siti has 8 kg of flour. Each cake needs 2/5 kg. How many cakes?

โœ” Multiply by reciprocal. Eight times five is forty, divided by two is twenty.

Q2. Ravi travels 10 km. Each segment is 1/4 km. How many segments?

โœ” Ten divided by one quarter is ten times four, which equals forty segments.

Q3. What is the first step in dividing whole number by fraction?

โœ” Keep Change Flip rule says change division sign to multiplication first.
Show transcript
[Slide 1] Understanding Division by Fractions
Hello class! Today we learn dividing whole numbers by fractions. Imagine Wei Ming has twelve dollars to buy stamps. Each stamp costs three quarters of a dollar.

[Slide 2] The Bar Model Method
We use the model method to visualise this problem clearly. Draw twelve blocks representing Wei Ming's money. Divide each block into four equal parts.

[Slide 3] The Calculation Rule
To solve, keep twelve and change divide to multiply. Then flip three quarters to become four thirds. This is called Keep Change Flip.

[Slide 4] Solving the Problem
Twelve times four is forty eight. Dividing forty eight by three gives us sixteen. Wei Ming can buy sixteen stamps in all.

[Slide 5] Common Mistake Alert
Students often forget to flip the fraction correctly. Remember, only the divisor gets inverted, not the whole number. Always check your work carefully.

[Slide 6] Quick Recap
Remember dividing by a small fraction makes a bigger number. Use the bar model and Keep Change Flip. You are ready for your PSLE exam!