Q2. Siti has y dollars. Mei Ling has three times as much.
✔ Three times y is written as 3y in algebra.
Q3. Cost of four buns at b dollars each plus two dollars.
✔ Four times b plus two is the correct expression.
Show transcript
[Slide 1] Introduction to Algebra
Welcome class. Today we learn algebra using Singapore contexts. Imagine you are buying chicken rice in Tampines.
[Slide 2] Writing Expressions Method
We replace unknown amounts with letters like x. Draw bars to visualise the parts clearly. This helps solve word problems easily.
[Slide 3] Worked Example Setup
Ravi buys noodles at a hawker centre near MRT. He pays for three packets and a delivery fee. Let us find the total cost expression.
[Slide 4] Worked Example Solution
We multiply three by x for the packets. Then add five dollars for the delivery fee. The bar model confirms this structure visually.
[Slide 5] Common Mistake Alert
Students often write three plus x instead of three times x. Remember letters next to numbers mean multiply. Always check your algebraic notation carefully.
[Slide 6] Quick Recap
You now know how to write simple expressions. Use bar models to check your work. Good luck with PSLE preparation.