KnowledgeMadeFun, home

Lesson · Grade 7 · Mathematics

Decimal to Percent and Back

  • Grade 7
  • Mathematics
  • 1 min 19 s
  • British Columbia
  • BC7-MA-26

The video uses a grid of 100 squares to show that 0.35 is 35 hundredths, which is 35 out of 100, or 35%. It then shows the quick way: to get a percent, multiply by 100 so the decimal point moves two places right, and to go back from 35% to 0.35, divide by 100 so it moves two places left, ending on a one-line recap.

Anyone can watch two lessons on the website without an account. Signing in is free, no payment and no card, and opens three a day; Plus has no limit.

Loading

Share to Google Classroom

In one sentence

The question this lesson answers

How do we change 0.35 to a percent, and back again?

Percent means out of 100, so picture a grid of 100 squares.

Transcript

What the lesson says

How do we change 0.35 to a percent, and back again?

Percent means out of 100, so picture a grid of 100 squares.

The decimal 0.35 means 35 hundredths, so we shade 35 squares.

That is 35 out of 100, which is 35 percent.

To change a decimal to a percent, multiply it by 100.

Multiplying by 100 moves the decimal point two places to the right.

The zero in front and the point at the end are not needed, so we drop them.

Then we write the percent sign, so 0.35 is 35 percent.

Now let us change 35 percent back to a decimal.

Take away the percent sign and divide by 100.

In 35, the decimal point is hiding after the 5.

Dividing by 100 moves the point two places to the left.

We write a zero in front of the point, and we are back to 0.35.

So multiply by 100 to get a percent, and divide by 100 to go back to a decimal.

Curriculum

Where this fits

British Columbia, Grade 7

Mathematics, Number: relationships between decimals, fractions, ratios, and percentsBC7-MA-26

Previous: Decimal to Fraction in Lowest FormNext: Fraction to Percent and Back

The outcomes and strands follow the British Columbia curriculum.

Keep going

More on this topic