Percentage practice questions

Secondary 1 topics, the foundation the O-Level Mathematics 4052 syllabus builds on. Every question below has a full worked solution.

When a student gets a question wrong in Math Amigo, it does not show the answer straight away. It reads the working, identifies the step that went wrong, and asks a question that points at the correction. The worked solution is there once a genuine attempt has been made.

Practise percentage free

What this topic covers

Worked examples

Example 1

Find 15.5%15.5\% of 240240.
Show the worked solution
  • $15.5\% \text{ of } 240 = \frac{15.5}{100} \times 240$
  • $= 37.2$

Answer: 37.237.2

Example 2

A factory produces 500 bulbs. 15% are found to be defective. How many bulbs are NOT defective?
Show the worked solution
  • Number defective $= 15\%$ of $500 = 75$
  • Number NOT defective $= 500 - 75$
  • $= 425$

Answer: 425425

Example 3

The cost of making furniture consists of: wood \250,paint, paint \5050, wages \100.Woodincreasesby. Wood increases by 8\%,paintincreasesby, paint increases by 25\%,andwagesdecreaseby, and wages decrease by 10\%$. Find the percentage increase in the total cost, correct to 1 decimal place where necessary.
Show the worked solution
  • Original total cost $= 250 + 50 + 100 = \$400$
  • New wood cost $= 250 \times 1.08 = \$270.00$
  • New paint cost $= 50 \times 1.25 = \$62.50$
  • New wages $= 100 \times 0.90 = \$90.00$
  • New total cost $= \$422.50$
  • Percentage increase $= \dfrac{22.50}{400} \times 100\%$
  • $= 5.6\%$ increase

Answer: 5.65.6

Questions parents ask

Is it really free?

The free plan is permanent and does not ask for a card. It has daily limits on the AI feedback, and the paid plans lift them.

Which syllabus does this follow?

O-Level Mathematics (4052), for Singapore secondary students. Math Amigo covers Secondary 1 to 4, both O-Level Mathematics and Additional Mathematics.

Will it just show my child the answer?

No. On a wrong answer it looks at the working, points to the step that went wrong, and asks a question that helps the student find the correction. The full worked solution is available after a genuine attempt.

Other Secondary 1 topics