Teen Numbers 11–19: One Ten and Some Ones | 1st Grade Math

Teen Numbers 11-19: One Ten and Some Ones - Grade 1 Math
Grade 1 Math  ›  Numbers & Place Value  ›  Lesson 3
Grade 1 Math - Numbers and Place Value

Teen Numbers 11-19: One Ten and Some Ones

Learn how teen numbers from 11 through 19 are built from one complete ten and some extra ones using base-ten models, ten-frames, place value charts, and expanded form.

This first grade math lesson helps students build, read, write, and represent teen numbers while developing a clear understanding of tens and ones.

Teen numbers 11-19 One ten and some ones Base-ten models Ten-frames Grade 1 place value

๐ŸŽฏ What You Will Learn

See one complete ten
Recognize that every number from 11 to 19 contains 1 ten.
Find the extra ones
Use the ones digit to tell how many ones come after the ten.
Build teen numbers
Use a ten rod, ones cubes, a ten-frame, and a place value chart.
Write expanded form
Connect 17 with 1 ten and 7 ones and with 10 + 7.
For parents & teachers — standards alignment: CCSS 1.NBT.B.2b states that the numbers 11 through 19 are composed of one ten and one, two, three, four, five, six, seven, eight, or nine ones. This lesson focuses directly on that special place-value structure.

๐Ÿง  Key Vocabulary

teen number — a number in the 11–19 group studied together for place value.
ten — a group of 10 ones.
ones — single units; in a teen number, they are the extra units beyond one ten.
tens place — the place on the left in a two-digit teen number; the digit 1 is in this place.
ones place — the place on the right; it tells how many extra ones there are.
expanded form — a way to show the value of the tens and ones, such as 17 = 10 + 7.

๐ŸŽˆ Meet the Teen Numbers

The numbers from 11 through 19 share the same place-value pattern. Each one has 1 ten and some extra ones. The ones digit tells how many extra ones there are.

11 12 13 14 15 16 17 18 19
Language note: The number words from 13 through 19 end in “-teen,” while 11 and 12 have special names. In words such as “thirteen,” the ones part can sound as if it comes first, so the place-value model is especially helpful. In elementary place-value lessons, all the numbers from 11 through 19 are often studied together because they all have the same structure: one ten and some ones.

๐Ÿ”Ÿ Start With One Full Ten

You do not need to count all the objects from 1 every time. Once 10 ones have been bundled into 1 ten, keep that ten together and count only the extra ones.

1 ten + 4 ones  =  10 + 4  =  14

๐ŸŸฃ Use a Full Ten-Frame

A full ten-frame is another way to see one complete ten. Extra counters outside the full frame show the ones. For example, a full ten-frame and 6 extra counters show 16.

10 + 6  =  16

๐Ÿ  Read the Two Places

In every teen number from 11 to 19, the digit 1 is in the tens place. It represents 1 ten, which has a value of 10. The digit on the right is in the ones place and tells how many extra ones there are.

Tens
Ones
1
8
18  =  1 ten and 8 ones  =  10 + 8
Common mix-up: In 18, the 1 does not mean 1 one and the 8 does not mean 8 tens. The 1 is in the tens place, so it means 1 ten. The 8 is in the ones place, so it means 8 ones.

๐ŸŒŸ 25 Worked Examples

✏️ Try each problem yourself first. Then tap “Show solution” to check your thinking.
1 Build 11
How many tens and ones are in 11?
✨ Show solution ๐Ÿ™ˆ Hide solution

11 has one group of ten and 1 extra one. Answer: 1 ten and 1 one.

2 Read a model for 12
What number is shown by 1 ten and 2 ones?
✨ Show solution ๐Ÿ™ˆ Hide solution

One ten is 10. Two extra ones make 12. Answer: 12.

3 Break apart 13
Complete: 13 = 1 ten and □ ones.
✨ Show solution ๐Ÿ™ˆ Hide solution

The ones digit in 13 is 3. Answer: 3 ones.

4 Make 14 from ten and ones
Complete: 14 = 10 + □.
✨ Show solution ๐Ÿ™ˆ Hide solution

14 is one ten and 4 ones, so 14 = 10 + 4. Answer: 4.

5 Read a ten-frame model
One full ten-frame and 5 extra counters show what number?
✨ Show solution ๐Ÿ™ˆ Hide solution

A full ten-frame shows 10. Five more counters make 15. Answer: 15.

6 Write 16 in expanded form
Write 16 as 10 plus some ones.
✨ Show solution ๐Ÿ™ˆ Hide solution

16 has one ten and 6 ones. Answer: 16 = 10 + 6.

7 Build 17
What number has 1 ten and 7 ones?
✨ Show solution ๐Ÿ™ˆ Hide solution

One ten is 10. Seven more ones make 17. Answer: 17.

8 Tens and ones in 18
How many tens and ones are in 18?
✨ Show solution ๐Ÿ™ˆ Hide solution

18 is made of one ten and 8 extra ones. Answer: 1 ten and 8 ones.

9 The largest teen number
How many tens and ones are in 19?
✨ Show solution ๐Ÿ™ˆ Hide solution

19 has one ten and 9 ones. It is the largest number in the 11–19 group. Answer: 1 ten and 9 ones.

10 Find the missing ones
Complete: 10 + □ = 13.
✨ Show solution ๐Ÿ™ˆ Hide solution

13 is one ten and 3 ones. Answer: 3.

11 Another missing part
Complete: 10 + □ = 18.
✨ Show solution ๐Ÿ™ˆ Hide solution

18 is one ten and 8 ones. Answer: 8.

12 Find the ten
Complete: □ + 6 = 16.
✨ Show solution ๐Ÿ™ˆ Hide solution

16 is 10 + 6, so the missing part is one ten. Answer: 10.

13 Use a place value chart
What number does this chart show?
Tens
Ones
1
7
✨ Show solution ๐Ÿ™ˆ Hide solution

The chart shows 1 ten and 7 ones. Answer: 17.

14 See 11 without recounting
What number is shown by one full ten-frame and 1 extra counter?
✨ Show solution ๐Ÿ™ˆ Hide solution

The full frame is already 10. One more makes 11. Answer: 11.

15 Eleven and twelve
Which number is 1 ten and 2 ones: 11 or 12?
✨ Show solution ๐Ÿ™ˆ Hide solution

11 is 1 ten and 1 one. 12 is 1 ten and 2 ones. Answer: 12.

16 Connect 13 to its parts
Which expression matches 13: 10 + 3 or 10 + 5?
✨ Show solution ๐Ÿ™ˆ Hide solution

One ten and 3 ones make 13. Answer: 10 + 3.

17 Build 14 with a full ten
A model has a full group of 10 and 4 single counters. What number is it?
✨ Show solution ๐Ÿ™ˆ Hide solution

Start with the full group of 10, then count 4 extra ones: 11, 12, 13, 14. Answer: 14.

18 Spot a place-value mistake
Mia says 15 is 5 tens and 1 one. What should she say?
✨ Show solution ๐Ÿ™ˆ Hide solution

The 1 is in the tens place and the 5 is in the ones place. Answer: 15 is 1 ten and 5 ones.

19 Check 16
Is this statement true? 16 = 1 ten and 6 ones.
✨ Show solution ๐Ÿ™ˆ Hide solution

Yes. One ten is 10, and 10 + 6 = 16. Answer: True.

20 Match 18 to a representation
Which shows 18: 1 ten and 8 ones, or 8 tens and 1 one?
✨ Show solution ๐Ÿ™ˆ Hide solution

18 has 1 in the tens place and 8 in the ones place. Answer: 1 ten and 8 ones.

21 Which number is in the teen group?
Which number is from 11 to 19: 9, 13, or 20?
✨ Show solution ๐Ÿ™ˆ Hide solution

13 is between 11 and 19. Answer: 13.

22 Value of the tens digit
In 17, what value does the digit 1 represent?
✨ Show solution ๐Ÿ™ˆ Hide solution

The digit 1 is in the tens place, so it represents one ten. One ten has a value of 10. Answer: 10.

23 Value of the ones digit
In 19, what does the digit 9 represent?
✨ Show solution ๐Ÿ™ˆ Hide solution

The digit 9 is in the ones place, so it represents 9 ones. Answer: 9 ones.

24 Same ten, different ones
What changes when you move from 15 to 16: the tens or the ones?
✨ Show solution ๐Ÿ™ˆ Hide solution

Both numbers have 1 ten. The ones change from 5 to 6. Answer: the ones.

25 Challenge: show 18 three ways
Write 18 as a numeral, as tens and ones, and in expanded form.
✨ Show solution ๐Ÿ™ˆ Hide solution

The numeral is 18. It has 1 ten and 8 ones. In expanded form, it is 10 + 8. Answer: 18; 1 ten and 8 ones; 10 + 8.

๐ŸŽฎ Independent Practice — 30 Problems

  1. Complete: 11 = 1 ten and □ one.
  2. Complete: 12 = 1 ten and □ ones.
  3. Complete: 14 = 1 ten and □ ones.
  4. Complete: 16 = 1 ten and □ ones.
  5. Complete: 19 = 1 ten and □ ones.
  6. Write the number: 1 ten and 3 ones = □.
  7. Write the number: 1 ten and 5 ones = □.
  8. Write the number: 1 ten and 8 ones = □.
  9. Complete: 10 + 2 = □.
  10. Complete: 10 + 4 = □.
  11. Complete: 10 + 7 = □.
  12. Complete: 10 + 9 = □.
  13. Complete: 13 = 10 + □.
  14. Complete: 15 = 10 + □.
  15. Complete: 18 = 10 + □.
  16. In 12, how many tens are there?
  17. In 12, how many ones are there?
  18. In 17, how many tens are there?
  19. In 17, how many ones are there?
  20. A base-ten model has 1 ten rod and 6 ones cubes. What number does it show?
  21. One full ten-frame and 4 extra counters show what number?
  22. True or false: 11 has 1 ten and 1 one.
  23. True or false: 18 has 8 tens and 1 one.
  24. Fix the mistake: “14 is 4 tens and 1 one.”
  25. Which numeral shows 1 ten and 9 ones: 19, 91, or 109?
  26. Which expanded form matches 16: 10 + 6 or 60 + 1?
  27. Complete: 10 + □ = 12.
  28. Complete: 10 + □ = 17.
  29. I have 1 ten and 8 ones. What number am I?
  30. Challenge: Write 13 in three ways: as a numeral, as tens and ones, and in expanded form.

๐Ÿ† Lesson Test — 15 Questions

  1. A number has 1 ten and 1 one. What number is it?
  2. Which numeral is made of 1 ten and 3 ones: 13, 31, or 103?
  3. Write 15 as 1 ten and some ones.
  4. How many extra ones are in 18?
  5. A base-ten model has 1 ten rod and 2 ones cubes. What number does it show?
  6. A place value chart shows 1 ten and 7 ones. What number does it show?
  7. True or false: 19 has 1 ten and 9 ones.
  8. Fix the mistake: “16 is 6 tens and 1 one.”
  9. Complete: 10 + □ = 14.
  10. Complete: 18 = □ + 8.
  11. Which numeral matches 1 ten and 2 ones: 12, 21, or 102?
  12. Write 17 in expanded form.
  13. How many tens are in 19?
  14. In 14, what value does the digit 1 represent?
  15. Challenge: A number is 10 + 9. Write the numeral and then write it as tens and ones.

๐Ÿ” Complete Answer Key

๐Ÿ”‘ Show practice answer key ๐Ÿ™ˆ Hide practice answer key

Practice Answers

1. 1
2. 2
3. 4
4. 6
5. 9
6. 13
7. 15
8. 18
9. 12
10. 14
11. 17
12. 19
13. 3
14. 5
15. 8
16. 1 ten
17. 2 ones
18. 1 ten
19. 7 ones
20. 16
21. 14
22. True
23. False — 18 has 1 ten and 8 ones.
24. 14 is 1 ten and 4 ones.
25. 19
26. 10 + 6
27. 2
28. 7
29. 18
30. 13; 1 ten and 3 ones; 10 + 3
๐Ÿ… Show test answer key ๐Ÿ™ˆ Hide test answer key

Test Answers

1. 11
2. 13
3. 1 ten and 5 ones
4. 8
5. 12
6. 17
7. True
8. 16 is 1 ten and 6 ones.
9. 4
10. 10
11. 12
12. 10 + 7
13. 1 ten
14. 10
15. 19; 1 ten and 9 ones

๐Ÿ’ก Common Mistakes to Watch For

Switching tens and ones
15 is 1 ten and 5 ones—not 5 tens and 1 one.
Recounting the full ten
Once you see a full group of 10, keep it as one ten and count only the extra ones.
Forgetting the value of the 1
In a teen number, the 1 is in the tens place and has a value of 10.
Reading the digits backward
17 means 1 ten and 7 ones. Reversing the digits gives 71, a different number.
For parents & teachers — Texas connection: Texas Grade 1 place-value expectations ask students to use concrete and pictorial models to compose and decompose numbers up to 120 and to represent numbers in forms including standard and expanded form. Teen numbers provide a clear first case for practicing those representations.

๐Ÿ–จ️ Printable Companion

A free Teen Numbers Practice Pack will be connected here as the MathLattice printable library grows. It will include ten-frames, base-ten models, matching activities, missing parts, expanded form, and an answer key.

← Lesson 2: Tens and Ones Grade 1 Math Hub Next: Compare and Order Two-Digit Numbers →

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