calculate 17.5% of £155 with no calculator

To calculate 17.5% of £155 without a calculator, you can follow these steps:

1. **Find 10% of £155:**
   - 10% is simply dividing by 10.
   \[
   10\% \text{ of } 155 = \frac{155}{10} = 15.5
   \]

2. **Find 5% of £155:**
   - 5% is half of 10%.
   \[
   5\% \text{ of } 155 = \frac{15.5}{2} = 7.75
   \]

3. **Find 2.5% of £155:**
   - 2.5% is half of 5%.
   \[
   2.5\% \text{ of } 155 = \frac{7.75}{2} = 3.875
   \]

4. **Add 10%, 5%, and 2.5%:**
   - Now, add the percentages together.
   \[
   10\% + 5\% + 2.5\% = 15.5 + 7.75 + 3.875 = 27.125
   \]

Thus, 17.5% of £155 is **£27.13** (rounded to two decimal places).

Would you like further details or any clarifications?

Here are some related questions:
1. What is 15% of £200?
2. How do you find 12.5% of a number without a calculator?
3. Can you explain how to calculate percentages using fractions?
4. How would you estimate 17.5% of £160?
5. What is the relationship between percentages and decimals?

**Tip:** When calculating percentages mentally, breaking them down into smaller percentages (like 10%, 5%, 1%) simplifies the process.

Learn how to calculate 17.5% of £155 without using a calculator. This step-by-step guide breaks the percentage into 10%, 5%, and 2.5% for easy mental calculation. Ideal for students in Grades 5-7, this method simplifies percentage calculation.

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