Find a percent of a quantity · lesson

Finding a percent of a number

💡 To find a percent of a number, write the percent as a decimal and multiply.

A percent is a number out of 100. So 40% means 40 out of 100, or 0.40.

To find 40% of a number, multiply the number by 0.40. You can also find 10% first, then multiply.

A percent over 100 gives more than the whole. 110% of a number is a bit more than the number.

🧠 Let's work it out

Find 40% of 65.

What do you think comes next?

💡 In a story, find the whole first, then take the percent of that whole.

Word problems hide the percent problem in a story. Find the whole amount. Then find the percent of it.

A discount is a percent of the price. The question may ask for the discount itself, not the new price.

If parts are given as percents, the rest is 100% minus those parts.

🧠 Let's work it out

A box has 90 stickers. 20% are gold and 30% are silver. The rest are blue. How many are blue?

What do you think comes next?

💡 To find what percent a part is, divide the part by the whole and multiply by 100.

Sometimes you know the part and the whole, but not the percent. Write a fraction: part over whole.

Then change it to a number out of 100. Divide, then multiply by 100.

🧠 Let's work it out

14 out of 40 kids like rain. What percent is that?

What do you think comes next?

💡 If you know a part and its percent, divide the part by the percent to find the whole.

Sometimes a problem says "14 is 40% of what number?" Here the whole is missing.

Write the percent as a decimal. Then divide the part by it. The whole should be bigger than the part when the percent is under 100%.

🧠 Let's work it out

14 is 40% of what number?

What do you think comes next?