Decimals & Percents · Understand percents · 5.1

Out of one hundred.

Percent means “per hundred”. 37% is 37 out of every 100 — the same as the decimal 0.37 and the fraction 37/100. They are three views of one amount.

01 / THE IDEA

See it work.

One picture, three forms

Out of one hundred.

37 of the 100 squares are shaded.

decimal0.37
percent37%
fraction37/100

Watch the method

Percent means “out of 100”

0.37 = 37% = 37/100.

1 / 2
0.370.37
1

Multiply by 100

Percent means “out of 100”, so ×100 — shift the point two places right.

0.37×1000.37 \times 100
2

Add the % sign

The result is the percent.

=37%= 37\%
02 / YOUR TURN

Practice until it feels automatic.

Your turn

Work it out.

Type a percent, e.g. 25%.

streak 0
best 0
… =
— / WHY IT WORKS

The idea underneath.

Three forms, one amount

Shade 37 of 100 squares: that is 0.37, 37%, and 37/100 all at once.

Why it works

37 shaded out of 100.

03 / WORKED EXAMPLES

From easy to tricky.

EX 1easy

Write 0.25 as a percent.

1

Multiply by 100

Percent means “out of 100”, so ×100 — shift the point two places right. 0.25 × 100

2

Add the % sign

The result is the percent. = 25%

EX 2medium

Write 0.2 as a percent.

1

Multiply by 100

Percent means “out of 100”, so ×100 — shift the point two places right. 0.2 × 100

2

Add the % sign

The result is the percent. = 20%

EX 3hard

Write 0.25 as a percent.

1

Multiply by 100

Percent means “out of 100”, so ×100 — shift the point two places right. 0.25 × 100

2

Add the % sign

The result is the percent. = 25%

04 / COMMON TRAPS

Where students slip.

Trap

Reading 0.37 as 3.7%.

Fix

0.37 = 37%, not 3.7%.

Trap

Forgetting the % sign.

Fix

A percent needs the % sign.

05 / QUIZ

Test yourself.

The Test

12 problems across three tiers. Auto-graded on submit. Hints and a full walkthrough on every question. Your work is saved on this device — sign in to keep it across devices.

0/12Answered
How to answerType just the value. Formatting won't trip you up — we ignore spaces, capital letters, commas, and subscript style, so t₁ = 5, d = 3 and t1=5,d=3 both count. For a list of numbers, separate them with commas (e.g. 3, 10, 17).
Core

Core (4)

C1

Write 0.25 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
C2

Write 0.1 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
C3

Write 0.8 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
C4

Write 0.125 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
Apply

Apply (4)

A1

Write 0.75 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
A2

Write 0.1 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
A3

Write 0.25 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
A4

Write 0.25 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
Extension

Extension (4)

E1

Write 0.75 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
E2

Write 0.75 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
E3

Write 0.05 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.
E4

Write 0.75 as a percent.

Need a hint?
  • Percent is out of 100.
  • Shade the squares to see all three forms.