Decimals & Percents · Understand percents · 5.2

Percent & decimal.

To turn a percent into a decimal, divide by 100 (shift the point two places left): 35% = 0.35. To go back, multiply by 100 (shift right): 0.35 = 35%.

01 / THE IDEA

See it work.

Watch the method

Percent ↔ decimal

35% = 0.35; 0.35 = 35%.

1 / 2
35%35\%
1

Divide by 100

“Per cent” is out of 100, so ÷100 — shift the point two places left.

35%÷10035\% \div 100
2

Drop the % sign

The result is the decimal.

=0.35= 0.35
02 / YOUR TURN

Practice until it feels automatic.

Your turn

Work it out.

Type a decimal, e.g. 0.75.

streak 0
best 0
… =
— / WHY IT WORKS

The idea underneath.

Shift two places

Out of 100 means dividing by 100 — move the point two places left for a decimal, right for a percent.

Why it works

35% → 0.35.

03 / WORKED EXAMPLES

From easy to tricky.

EX 1easy

Write 60% as a decimal.

1

Divide by 100

“Per cent” is out of 100, so ÷100 — shift the point two places left. 60% ÷ 100

2

Drop the % sign

The result is the decimal. = 0.6

EX 2medium

Write 5% as a decimal.

1

Divide by 100

“Per cent” is out of 100, so ÷100 — shift the point two places left. 5% ÷ 100

2

Drop the % sign

The result is the decimal. = 0.05

EX 3hard

Write 40% as a decimal.

1

Divide by 100

“Per cent” is out of 100, so ÷100 — shift the point two places left. 40% ÷ 100

2

Drop the % sign

The result is the decimal. = 0.4

04 / COMMON TRAPS

Where students slip.

Trap

Shifting only one place.

Fix

÷100 moves the point TWO places.

Trap

Shifting the wrong way.

Fix

Percent → decimal moves left.

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 15% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
C2

Write 40% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
C3

Write 15% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
C4

Write 25% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
Apply

Apply (4)

A1

Write 25% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
A2

Write 25% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
A3

Write 25% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
A4

Write 20% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
Extension

Extension (4)

E1

Write 25% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
E2

Write 25% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
E3

Write 5% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.
E4

Write 60% as a decimal.

Need a hint?
  • Move the point two places.
  • Left for a decimal, right for a percent.