Lesson 86: Place value — tens and ones

🧮 MATH (40 Lessons) • 🟢 A. Numbers and Counting

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Objective

I can show a 2-digit number using tens and ones. I can say how many tens and how many ones are in a number like 23.

Materials

Mini-lesson — Tens and ones in 2-digit numbers

A 2-digit number (like 23) is made from tens and ones.

Tens

  • Ten ones can be grouped into one ten.
  • We can show one ten with a bundle of 10 sticks or a long rod.
  • Two tens means 20, three tens means 30, and so on.

Ones

  • Ones are the single pieces that are not in a bundle of ten.
  • If you have 3 loose cubes, that is 3 ones.
  • Ones change the last digit of the number (for example, the 3 in 23).

Reading a number like 23

  • In 23, the 2 means 2 tens (20).
  • The 3 means 3 ones.
  • So 23 is 2 tens and 3 ones.

You will build numbers with tens (bundles) and ones (single pieces), then read them out loud.

Picture strip: Tens rods and ones cubes.

20 = 2 tens, 0 ones

23 = 2 tens, 3 ones

Guided Practice — Build numbers with tens and ones

You will use real objects to build numbers with tens and ones. Then you will trace important place value words.

  1. Make tens: Count 10 sticks and tie them or line them up as one bundle. This is 1 ten.
  2. Make ones: Keep some small objects as single ones.
  3. Build a number: Choose a 2-digit number between 11 and 39 (for example, 24). Build it using bundles of ten and single ones.
  4. Say the tens and ones: For your number, say out loud:
    "24 is 2 tens and 4 ones."
  5. Write on paper: On your paper, write your number and a matching sentence. Example:
    24 = 2 tens and 4 ones.
  6. Use the tracing pad: Choose two words that match your work (for example, tens and ones) and trace them on the pad.
  7. Add a small picture: Next to the word tens, draw a tiny rod. Next to the word ones, draw a tiny cube.
Tracing Pad
Tracing snapshot for print
Tip: After you trace tens and ones, write a short line such as "23 = 2 tens, 3 ones." and draw a tiny rod for each ten and a tiny cube for each one.

Practice 1 — Tens and ones with models

[PLACEHOLDER PRACTICE 1]

Practice 2 — Match numbers to tens and ones

[PLACEHOLDER PRACTICE 2]

Practice 3 — Place value stories

[PLACEHOLDER PRACTICE 3]

Quick Check — Place value: tens and ones

Answer each question about tens, ones, and 2-digit numbers. You may look back at the mini-lesson.

1) In the number 23, what does the 2 mean?

In 23, the 2 is in the tens place, so it means 2 tens.

2) In the number 23, what does the 3 mean?

The last digit shows the ones. 3 means 3 ones.

3) How many tens are in 40?

40 is 4 groups of ten, so 4 tens.

4) How many ones are in 40?

The ones digit is 0, so there are 0 ones.

5) Which number has 2 tens and 5 ones?

2 tens and 5 ones makes 25.

6) Which number has 3 tens and 1 one?

3 tens and 1 one is 31 (not 13).

7) A model shows 1 ten and 7 ones. Which number is it?

1 ten (10) and 7 ones makes 17.

8) A model shows 2 tens and 0 ones. Which number is it?

2 tens is 20. Zero ones does not change the number.

9) Which part of a 2-digit number shows the tens?

In a 2-digit number, the left digit shows the tens place.

10) Which part shows the ones?

The last digit is the ones place.

11) Which number shows the same tens but more ones than 42?

47 has 4 tens like 42, but 7 ones, which is more than 2 ones.

12) Which picture matches 34?

34 is 3 tens and 4 ones.

13) A model shows 4 tens and 2 ones. How do we say it?

We say it as four tens and two ones (42).

14) Why is place value important?

Place value tells us what each digit stands for in a number.

15) Which sentence is true?

25 has 2 tens (20) and 5 ones.

Assessment (parent/teacher)

Exit ticket (student)

Next time I will practise…

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