Significant figures are used to show how precise a number is. Rounding to a given number of significant figures works for both whole numbers and decimals, especially when numbers are very large or very small.

The first significant figure is the first non-zero digit in a number. All digits after this can also be significant, depending on the level of accuracy required.

To round to a given number of significant figures:

• Find the first non-zero digit
• Count along to the required number of significant figures
• Look at the next digit to decide whether to round up or down

Examples:

• 4,738 rounded to 2 significant figures is 4,700
• 0.05642 rounded to 2 significant figures is 0.056
• 12.349 rounded to 3 significant figures is 12.3

After rounding, any digits after the required significant figures are removed. Zeros may be added as placeholders to keep the number’s size correct.

Rounding to significant figures is widely used in science, measurements, and data handling where clarity and appropriate accuracy matter more than exact values.