6 × 100 means 6 groups of one hundred. That is 6 hundreds, which is 600.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
Not "add zeros"
The zeros appear because you counted hundreds. Saying "add two zeros" hides the reason.
Multiples of ten and a hundred
6 × 300 is 6 groups of 3 hundreds, which is 18 hundreds, which is 1,800.
Why the zeros appear
6 × 100 is 6 hundreds, which is 600. The digit 6 has moved two places to the left and zeros hold the vacated places. Saying "add two zeros" is a fair shortcut, but the real reason is that the units got a hundred times bigger.
Counting all the zeros
40 × 300 is 4 × 3 = 12 with three zeros: 12,000. Count the zeros from both factors and attach them all. This handles a huge range of calculations without any written method at all.
The basis of every estimate
Estimating 387 × 42 as 400 × 40 = 16,000 uses exactly this skill. Being quick and confident with multiples of ten is what makes estimation fast enough to be worth doing — which in turn is what keeps your exact answers honest.
The shortcut has a limit
"Add a zero" works for whole numbers only. Once decimals arrive, 6.3 × 10 is 63, not 6.30. The digits move a place; a zero is simply what fills the gap when there is nothing else to move in. Learn the movement, not the zero.
Step 2: Try It Yourself
Tap and try it out.
6 × 3 = 18
6 rows of 3 makes 18.
Step 3: Watch an Example
One step at a time.
Watch Leo Count Hundreds
Leo works out 7 × 400.
- Step 1
He reads 400 as 4 hundreds.
Step 4: Your Turn
Practice makes it stick.
The Crates
Problem 1 of 2
8 crates each hold 200 apples. How many apples?
apples
The Boxes
Problem 2 of 2
5 boxes each hold 3,000 sheets. How many sheets?
sheets
Count the Units
1 of 4
7 × 100 = ?
2 of 4
4 × 600 = ?
3 of 4
9 × 50 = ?
4 of 4
6 × 2,000 = ?
Step 5: Quick Check
Show what you know.
Question 1 of 2
8 × 700 = ?
Question 2 of 2
Why does 6 × 100 end in two zeros?
What You Learned
- Multiplying by 100 means counting hundreds.
- The zeros appear because of the unit, not by a rule.
- Multiples work the same way: 6 × 300 is 18 hundreds.