Multiplying and dividing by powers of ten, step by step

Multiplying and dividing by 10, 100, and 1000 is not really multiplication — it is the decimal point moving.

The question

1.2 × 100

1.2×100
12
120
  1. 100 is 10 × 10, so there are 2 moves to make — one for each ten.
  2. × 10 — every digit is worth ten times as much, so the point steps one place right: 12.
  3. And × 10 again — every digit is worth ten times as much, so the point steps one place right: 120. The digits never changed — only where the point sits. 1.2 × 100 = 120.

How it works.

  1. 01

    100 is 10 × 10, so there are 2 moves to make — one for each ten.

  2. 02

    × 10 — every digit is worth ten times as much, so the point steps one place right: 12.

  3. 03

    And × 10 again — every digit is worth ten times as much, so the point steps one place right: 120. The digits never changed — only where the point sits. 1.2 × 100 = 120.