Kindergarten · K.NBT.A.1

Numbers 11-19 in kindergarten

Numbers 11-19 are the teen numbers, and each one is made of ten ones and some more ones. In kindergarten, your child learns to see 13 as 10 and 3 more, to show it with objects or drawings and to write it as $13 = 10 + 3$ .

What the standard says

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

K.NBT.A.1 Compose and decompose numbers from 11 to 19 into ten ones and some further ones, e.g., by using objects or drawings, and record each composition or decomposition by a drawing or equation (e.g., 18 = 10 + 8); understand that these numbers are composed of ten ones and one, two, three, four, five, six, seven, eight, or nine ones.

What it means, in plain words

A teen number is any number from 11 to 19. Every teen number is 10 ones plus 1 to 9 more ones. The number 12 is 10 and 2 more, and the number 19 is 10 and 9 more. The 1 at the start of a teen number stands for the group of 10 ones.

A ten-frame shows this clearly. A ten-frame is a box with 2 rows of 5 spaces, so it holds exactly 10 counters. To show a teen number, your child fills one ten-frame and puts the extra ones in a second frame.

Your child also writes what the objects show as an equation, a number sentence with an equals sign, like $12 = 10 + 2$ . Numbers 11-19 in kindergarten prepare for place value in 1st grade, where 10 ones become one ten.

Your child should be able to:

Show any number from 11 to 19 as 10 objects and some more
Fill a ten-frame and say how many more ones a teen number needs
Write a teen number as an equation, like $18 = 10 + 8$
Say which teen number $10 + 9$ makes

Example

How can your child show 13 with pennies?

Count out 10 pennies and put them in a row. That row is the group of ten ones.
Count out 3 more pennies and put them to the side.
Count them all: 10 and 3 more is 13.
So 13 is ten ones and 3 more ones, and the equation is $13 = 10 + 3$ .

Where children usually get stuck

Your child writes 31 for thirteen.
In "thirteen" the three sound comes first, so the child writes the 3 first. The name of the number runs in the opposite order from its digits.
What helps. Show 13 with 10 pennies and 3 pennies. Write the 1 under the group of 10 and the 3 under the 3 pennies, so the order on paper matches the objects.
Your child counts every object from 1 up to 18, even when 10 of them fill a ten-frame.
The child does not yet trust that a full ten-frame is always 10. Counting from 1 feels safer.
What helps. Draw a ten-frame on paper and fill it with buttons together a few times. Then start the count at 10 for the extra ones: 11, 12, 13.
Your child can show 18 but cannot say what is inside eleven or twelve.
Eleven and twelve do not sound like ten and one or ten and two. Their names hide the pattern that thirteen to nineteen show.
What helps. Say them the long way together, "ten and one" and "ten and two". Then build each one with 10 objects and 1 or 2 more.

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
Which equation matches the ten-frames?
A
$\displaystyle 10 + {}$
$\displaystyle 1 = {}$
$\displaystyle 11$
B
$\displaystyle 10 + {}$
$\displaystyle 5 = {}$
$\displaystyle 15$
C
$\displaystyle 10 + {}$
$\displaystyle 7 = {}$
$\displaystyle 17$
D
$\displaystyle 10 + {}$
$\displaystyle 1 = {}$
$\displaystyle 21$
Show the answer and how to solve it
The answer is $10 + 1 = 11$ because one ten-frame shows ten ones and the other ten-frame shows one more one.
1. 1The first ten-frame is full and shows 10 counters. The second ten-frame shows 1 more counter.
2. 2Add 10 and 1 to find the total.
3. 3The equation $10 + 1 = 11$ matches the picture.
Common mistake. A common mistake is miscounting the ones in the second ten-frame, or confusing 11 with 21.
The idea underneath. A teen number is ten ones and some more ones.
2On level
Show 14 on the ten-frames.
Tap or click a box to add a counter; tap a filled box to remove one.
Show the answer and how to solve it
Answer. 14
The ten-frames show 14 when the first frame is full with 10 counters and the second frame has 4 more counters. Ten ones and 4 more ones make 14.
1. 1Look at the first ten-frame. It already shows 10 counters.
2. 2To show 14, you need ten ones and 4 more ones.
3. 3Tap 4 empty cells in the second ten-frame to add 4 more counters.
4. 4Now the ten-frames show 14. Ten ones and 4 more ones make 14.
Common mistake. A common mistake is adding 3 ones instead of 4. Count the extra ones carefully: 1, 2, 3, 4.
The idea underneath. Every teen number is made of ten ones and some more ones. The first full ten-frame shows the ten, and the extra ones in the second frame show the rest.
3On level
$\displaystyle 10 + \underline{\phantom{00}} = 14$
What number goes in the blank?
Show the answer and how to solve it
Answer. 4
The missing number is $4$ , because $10 + 4 = 14$ .
1. 1Look at the equation. We need to find the missing number that makes the equation true.
2. 2A teen number is ten ones and some more ones. $14$ is $10$ ones and $4$ more ones.
3. 3The missing number is $4$ , because $10 + 4 = 14$ .
Common mistake. A common mistake is typing $1$ instead of $4$ . Some students see the $1$ in $14$ and copy that. But $14$ is made of $10$ ones and $4$ more ones. The $10$ is already on the left side of the equation, so we need to find how many more ones — which is $4$ .
The idea underneath. Every teen number from $11$ to $19$ can be made by adding $10$ and some more ones. The missing ones tell you how many more after $10$ .
4Stretch
The ten-frames below show a teen number.
Drag tiles to build the equation that matches the ten-frames.
Tap or click a tile to drop it into the highlighted blank, or tap an empty blank first to choose a different one. Tap a filled blank to send its tile back.
10
+
=
7
71
8
6
17
Tap an item to place it in the next empty slot, or drag it to a specific slot. With a keyboard: select an item with Enter or Space, then select a slot to place it. Press Delete or Backspace on a slot to remove an item.
Show the answer and how to solve it
The ten-frames show 17. The matching equation is $10 + 7 = 17$ .
1. 1Look at the ten-frames. The first frame is full, so it shows 10 ones.
2. 2Count the ones in the second ten-frame. There are 7 more ones.
3. 3Put together 10 ones and 7 more ones to make 17. Drag the 7 into the first box and the 17 into the second box.
Common mistake. A common mistake is writing the teen number with the numbers in the wrong order, choosing 71 instead of 17. Another mistake is miscounting the ones in the second frame — choosing 6 or 8 instead of 7.
The idea underneath. A teen number is made of ten ones and some more ones. The 10 always stays the same; only the extra ones change.