Math Lab
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Percent of a Number

Percentages · Class VII

Compute p% of n by sliding both.

200
type a value
0500
25 %
type a value
0100
Live values
  • p% of n50
  • Remainder150
xy
  • p% of n as p varies

Formulas in this lab

  • p% of n
    p100 n\dfrac{p}{100}\,n
  • Remainder
    n−p100 nn - \dfrac{p}{100}\,n
Tip: Output rises linearly with percent; at 100% you recover the full number.

Frequently asked questions

▶How do I calculate p% of a number?

Multiply the number by p and divide by 100. So 18% of 500 is 18 * 500 / 100 = 90. The lab lets you slide p and n to see the answer change in real time.

▶How do I use the percent explorer lab?

Slide n between 0 and 500 and p between 0 and 100. The lab shows p% of n and also the remainder, which is n minus that percent. Try n = 200 and p = 25 to see 50 and 150.

▶How are percentages used in Indian shops and exams?

GST of 18% on a Rs 500 phone case adds 18 * 500 / 100 = 90, so you pay Rs 590. In exams, scoring 80% on a 60-mark test means 48 marks. The lab confirms both kinds of calculations quickly.

▶Percent of vs percent off: what is the difference?

Percent of finds a portion: 25% of 200 is 50. Percent off subtracts it: 25% off Rs 200 means you pay 200 - 50 = 150. The lab shows both: the p% of n value and the remainder n - p% of n, which is exactly the percent-off price.