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Multiplication Tricks

Multiplying by 25 – Divide by 4, Times 100

Four 25s make 100, so multiplying by 25 is the same as dividing by 4 and multiplying by 100.

This page explains the rule, shows why it works, and walks through worked examples. Then you can try it yourself and check your understanding with practice questions. Use the previous and next links at the bottom to move through the tricks in order.

The rule

The Rule: To multiply by 25, divide by 4 and then multiply by 100.

Why it works

Why It Works: 25 is exactly a quarter of 100. Dividing by 4 first keeps the numbers small and friendly to work with, and multiplying by 100 at the very end is just adding two zeros — no hard multiplication required at any point.

Formal Proof (for advanced learners)

25 = 100 ÷ 4, so n×25 = n×(100÷4) = (n÷4)×100, again by associativity of multiplication and division.

Examples

  • 16 × 25 → 16 ÷ 4 = 4, then ×100 = 400.
  • 48 × 25 → 48 ÷ 4 = 12, then ×100 = 1200.
  • 37 × 25 → 37 ÷ 4 = 9.25, then ×100 = 925.

Step by step

Example A: 64 × 25

  1. Divide by 4: 64 ÷ 4 = 16.
  2. Multiply by 100: 16 × 100 = 1600.

Example B: 30 × 25

  1. Divide by 4: 30 ÷ 4 = 7.5.
  2. Multiply by 100: 7.5 × 100 = 750.

Try it yourself

Now it is your turn. A new random question appears each time. Type your answer in the box and press Check Answer. If you are right, we show how the trick got you there, step by step. If you are not, you will see the full working two ways, the shortcut and the usual method, so you can spot exactly where your answer differed. Press New Question as often as you like: a few quick rounds is the best way to make the trick feel automatic.

Try It Yourself

Practice questions

Have a go on paper first, then tap Show answer to check your method.

  1. Work out 16 × 25.

    Show answer

    400. Divide by 4: 16 ÷ 4 = 4. Multiply by 100: 4 × 100 = 400.

  2. Work out 36 × 25.

    Show answer

    900. Divide by 4: 36 ÷ 4 = 9. Multiply by 100: 9 × 100 = 900.

  3. Work out 52 × 25.

    Show answer

    1300. Divide by 4: 52 ÷ 4 = 13. Multiply by 100: 13 × 100 = 1300.

  4. Work out 90 × 25.

    Show answer

    2250. Divide by 4: 90 ÷ 4 = 22.5. Multiply by 100: 22.5 × 100 = 2250.

  5. A box holds 25 pencils. How many pencils are in 84 boxes?

    Show answer

    2100. Divide by 4: 84 ÷ 4 = 21. Multiply by 100: 21 × 100 = 2100.

Tips and watch-outs

  • It works because 25 = 100 ÷ 4.
  • Numbers that are not multiples of 4 still work: 26 ÷ 4 = 6.5, and 6.5 × 100 = 650.