Kindergarten · K.CC.A.1

Counting to 100 in kindergarten

Counting to 100 is one of the main goals of kindergarten math. By the end of the year, your child says the numbers from 1 to 100 in order, out loud and without skipping any. Your child also learns counting by tens: 10, 20, 30 and on up to 100.

What the standard says

The official Common Core wording, quoted exactly. The plain version follows.

K.CC.A.1 Count to 100 by ones and by tens.

What it means, in plain words

Counting to 100 in kindergarten is about the order of the number names. Your child says one, two, three and keeps going, with every number in its place. At this stage it is counting from memory, a bit like a long song. Counting real objects is a separate skill that grows alongside it.

The numbers after 20 follow a pattern. Each group of ten numbers, such as the twenties or the thirties, runs through one to nine: twenty-one, twenty-two and up to twenty-nine. Then a new ten starts with thirty. Once your child hears this pattern, the count gets much easier. The hard spots are the numbers from 11 to 19, which do not follow the pattern, and the places where one ten turns into the next.

Counting by tens means saying only the numbers that end in zero: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100. Each one is ten more than the one before. A hundred chart (a grid of the numbers 1 to 100 in rows of ten) shows this well, because those numbers all sit in the last column.

Your child should be able to:

Count out loud from 1 to 100 by ones without skipping a number
Say the number that starts the next ten, such as 60 after 59
Count by tens from 10 to 100
Point to the numbers that end in zero on a hundred chart

Example

There are 6 bundles of straws with 10 straws in each bundle. How many straws are there?

Each bundle holds 10 straws, so count by tens and say one number for each bundle.
Touch the bundles one at a time: 10, 20, 30, 40, 50, 60.
The last number is 60, so there are 60 straws.

Example

What number comes after 69 when you count by ones?

Sixty-nine is the last number in the sixties.
After a number that ends in nine, the next ten starts, so sixty turns into seventy.
The number after 69 is 70.

Where children usually get stuck

Your child counts "twenty-eight, twenty-nine, twenty-ten, twenty-eleven".
Your child has picked up that the second part of the number goes up by one each time. Nothing in that pattern says what comes after nine, so twenty-ten sounds right.
What helps. Count together on a hundred chart. When you reach a number that ends in nine, stop and point to the first number of the next row. Read that new number together before going on.
Your child skips 15, says "fiveteen", or mixes up thirteen and thirty.
The numbers from 11 to 19 break the pattern. Eleven and twelve sound like no other number, thirteen and fifteen do not sound like three and five, and thirteen and thirty sound almost the same.
What helps. Say the numbers from 11 to 19 slowly while you point to them on the chart. Then say thirteen and thirty one after the other and let your child hear the different endings.
When counting by tens, your child says "twoty" for 20 or "fivety" for 50.
Your child has noticed a real pattern: four and forty, six and sixty. Twenty, thirty and fifty are the names that break it, so your child builds them the regular way.
What helps. Count by tens with bundles of 10 sticks or 10 pennies in a pile. Say each tens name together as you push a bundle across the table.

Try four practice questions

Real kindergarten questions from our question bank, easiest first. Answer them right here, check each one, and see a worked solution for any question.

1Warm-up
James tapped numbers on the hundred chart in order, counting by ones.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
What was the last number James tapped?
A
5
B
7
C
8
D
12
Show the answer and how to solve it
The answer is 7 because 7 is the last shaded number on the chart.
1. 1Look at James's hundred chart. The shaded boxes show the numbers James tapped, starting at 1.
2. 2Find the last shaded box on the chart. That is the last number James tapped.
3. 3The last shaded box is 7. So James's last number was 7.
Common mistake. A common mistake is being off by one — picking the number just before (6) or just after (8) the last shaded box.
The idea underneath. The last number you tap when counting by ones is the largest shaded number — it tells how many you counted in all.
2Warm-up
Lin is counting from 1. One number is missing.
Lin's count:
$\displaystyle 1, \underline{\phantom{00}}, 3, 4$
Which number is missing?
A
2
B
7
C
9
D
11
Show the answer and how to solve it
The missing number is 2. When counting by ones from 1, the number that comes after 1 and before 3 is 2.
1. 1Look at Lin's count. Find the spot with the blank.
2. 2When you count by ones from 1, the order is 1, 2, 3, 4. The number that comes after 1 and before 3 is 2.
3. 3So the missing number is 2.
Common mistake. A common mistake is picking a number that is already shown in the count, like 1 or 3. The missing number is the one that is NOT in the sequence yet — the number that fills the blank between 1 and 3.
The idea underneath. When counting by ones, each number is one more than the number before it. The number in the blank is one more than 1 and one less than 3 — that is 2.
3On level
Fill in the missing number to complete the count by tens.
,20,30,40,50
Show the answer and how to solve it
The missing number is 10. When you count by tens, 10 comes right before 20.
1. 1Look at the count by tens: 20, 30, 40, 50.
2. 2Each number is 10 more than the one before it.
3. 3The missing number comes before 20. Take 10 away from 20 to find it.
4. 4The missing number is 10.
Common mistake. A common mistake is typing 20 again instead of 10. The blank comes before 20, so the missing ten is 10 — one step back in the count.
The idea underneath. Each number in a count by tens is 10 more than the number before it.
4On level
Liam was counting by ones to 20. The chart shows the numbers he tapped. Liam missed exactly one number.
Liam's chart:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Which number did Liam miss?
A
6
B
7
C
8
D
17
Show the answer and how to solve it
The missing number is 7. When Liam tapped the numbers in order from 1 to 20, he skipped over 7. You can see the empty cell on the chart between 6 and 8.
1. 1Look at Liam's chart. Liam was counting from 1 to 20, and the cells he tapped are colored.
2. 2Find the cell that is NOT colored between 1 and 20. The empty cell is between 6 and 8.
3. 3The empty cell is 7. Liam skipped over 7 when he counted.
Common mistake. A common mistake is picking 17 because it ends in the same digit as 7. But 17 is shaded on the chart, so Liam did tap it. The missing number is the empty cell between 6 and 8.
The idea underneath. When you count in order on a chart, every number gets tapped. A number that gets skipped leaves an empty cell. Find the empty cell, and you find the missed number.