Counting by Tens to 100

Learn to count forward by tens, starting at 10 and ending at 100, by adding ten each time.

Reading is good — doing is better. Practice Counting by Tens to 100 as an interactive lesson.

Definition

Counting by tens means you skip all the numbers in between and only say every tenth number: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100. Each number is exactly ten more than the one before it.

Remember the rule

Start at 10, then keep adding 10. Every decade number ends in zero: 10, 20, 30 … 100. Ten tens make one hundred!

Key words

Skip counting: Jumping over some numbers and only counting every second, fifth, or tenth number instead of counting one by one.
Ten: The number that comes after nine; it looks like a 1 followed by a 0.
Decade number: A number you land on when counting by tens, like 10, 20, 30, all the way to 100.
Hundred: The number 100; it is the same as ten tens put together.
Pattern: Something that repeats in a predictable way, like the way decade numbers always end in a zero.
More: A bigger amount; when we count by tens, each new number is ten more than the last one.

Worked examples

Say the decade numbers in order from 10 to 100.

→ 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 · Notice that every single number ends in a zero — that is the pattern for counting by tens.

What number comes after 40 when counting by tens?

→ 50 · 40 plus 10 equals 50, so you jump from 40 straight to 50.

What number comes after 80 when counting by tens?

→ 90 · Just add ten more: 80 plus 10 equals 90.

Fill in the blank: 10, 20, ___, 40, 50

→ 30 · The missing number is between 20 and 40, and 20 plus 10 equals 30.

How many tens do you count to reach 100?

→ Ten tens: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 — that is 10 jumps of ten. · Counting on your fingers, you use all ten fingers once to land on 100.

A child has 5 bags with 10 crayons each. Count by tens to find the total.

→ 10, 20, 30, 40, 50 — there are 50 crayons in all. · Counting by tens makes it much faster than counting every single crayon one by one.

Common mistakes

Skipping a decade number, for example saying 10, 20, 30, 50 and forgetting 40.
Saying a number that does not end in zero, like 10, 20, 35, 40 — every decade number must end in 0.
Stopping before 100, for example stopping at 90 and thinking the count is finished.
Counting by ones inside the skip, like saying 10, 11, 12 … 20 instead of jumping straight from 10 to 20.
Confusing the order and going backwards, for example saying 30, 20, 40 out of sequence.

FAQs

Why do we learn to count by tens?

Our number system is built on tens, so counting by tens helps you add, count money, read a clock, and understand bigger numbers much more easily.

Do all the numbers when counting by tens end in zero?

Yes! Every time you count by tens — 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 — the number always ends in a zero. That zero is your clue that you are on the right track.

What comes after 100 if we keep counting by tens?

You would say 110, 120, 130, and so on, but in Kindergarten we practice just up to 100.

How can I help my child practice counting by tens at home?

Try counting stacks of 10 pennies, skipping by tens on a number line, or singing a count-by-tens song together all the way to 100.

Is 100 a decade number?

Yes! 100 is the last stop when we count by tens to 100. It equals ten tens, and it ends in zero just like all the others.

What if my child keeps forgetting a number like 70 or 80?

Practice saying the sequence slowly every day and point to each number on a hundreds chart. Seeing the numbers while saying them helps the brain remember the order.

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