Decimals & Percents · Multiply decimals · 3.3

Multiply by tens.

Multiplying by a power of ten just shifts the decimal point right — one place for each zero. 3.45 × 100 shifts two places → 345.

01 / THE IDEA

See it work.

Watch the method

Multiply by 10, 100…

3.45 × 100 = 345.

1 / 2
3.45×1003.45 \times 100
1

Count the zeros

×100 shifts the decimal point 2 place(s) to the right.

3.45×1003.45 \times 100
2

Shift the point

Move the point right and fill with zeros if needed.

=345= 345
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.

Count the zeros

Each zero in the power of ten moves the point one place right; fill empty places with zeros.

Why it works

3.45 → ×100 → 345.

03 / WORKED EXAMPLES

From easy to tricky.

EX 1easy

Multiply 9.96 × 1000

1

Count the zeros

×1000 shifts the decimal point 3 place(s) to the right. 9.96 × 1000

2

Shift the point

Move the point right and fill with zeros if needed. = 9960

EX 2medium

Multiply 8.71 × 100

1

Count the zeros

×100 shifts the decimal point 2 place(s) to the right. 8.71 × 100

2

Shift the point

Move the point right and fill with zeros if needed. = 871

EX 3hard

Multiply 7.75 × 100

1

Count the zeros

×100 shifts the decimal point 2 place(s) to the right. 7.75 × 100

2

Shift the point

Move the point right and fill with zeros if needed. = 775

04 / COMMON TRAPS

Where students slip.

Trap

Shifting the wrong direction.

Fix

Multiplying moves the point right.

Trap

Miscounting the zeros.

Fix

×100 has two zeros → two places.

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

Multiply 1.55 × 1000

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
C2

Multiply 4.02 × 10

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
C3

Multiply 6.59 × 1000

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
C4

Multiply 1.19 × 100

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
Apply

Apply (4)

A1

Multiply 5.79 × 10

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
A2

Multiply 5.89 × 1000

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
A3

Multiply 9.81 × 1000

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
A4

Multiply 9.19 × 10

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
Extension

Extension (4)

E1

Multiply 6.91 × 100

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
E2

Multiply 0.96 × 100

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
E3

Multiply 8.01 × 10

Need a hint?
  • Count the zeros.
  • Move the point that many places right.
E4

Multiply 0.45 × 10

Need a hint?
  • Count the zeros.
  • Move the point that many places right.