Lia's Maths Book
Place Value · Number lines
- Part 1 · 10s on the line
- Part 2 · 10s and 1s
- Part 3 · What is each step worth?
- Part 4 · Estimate the arrow
- Part 5 · Mark the number
- Part 6 · Think about it
10s on the line
Today I will: count in 10s along a number line.
There are 10 intervals from 0 to 100.
Each interval is worth 10. Count in 10s.
Each interval is worth 10.
Label the number line. Count in 10s.
The last line starts at 30, not 0.
What number is the arrow pointing to?
10s and 1s
Today I will: read and place numbers between two 10s.
Read the first number first. This line starts at 40.
Count on from 40: 41, 42, 43 … 47.
47 is between 40 and 50. It is closer to 50.
Complete the number line.
What number is the arrow pointing to? Start at the nearest 10.
Draw an arrow to show where each number goes.
What is each step worth?
Today I will: find what each interval is worth, then count in that step.
Count the intervals between two numbers.
5 intervals make 10, so each interval is worth 2: 2, 4, 6, 8, 10.
What is each interval worth?
Complete the number line.
Look at the number lines in 1. What is each interval worth?
What number is the arrow pointing to?
Estimate the arrow
Today I will: estimate the number an arrow is pointing to.
1. Find halfway.
2. Is the arrow closer to 0, to halfway or to 100?
3. Split the line into 10 jumps in your head.
4. Check from the nearest number you know.
A good estimate is close. It does not have to be exact.
A is about 90.
Estimate the number the arrow is pointing to.
Look at the numbers at the ends first. Halfway is not always 50.
Mark the number
Today I will: draw an arrow to show where a number goes.
Is the number more or less than halfway?
Small numbers go close to 0. Big numbers go close to 100.
10 goes close to 0.
Draw an arrow to show where each number goes.
Your arrow does not have to be exact. Close is good.
Think about it
Today I will: check a friend's answer and explain how I know.
Read what the friend says. Is the friend right?
Write or draw your answer. Then tell a grown-up how you know.
Is the friend right? Tell a grown-up why.
Ben says arrow A points to 6. Is Ben right? Tell a grown-up why. Then write the number that arrow A points to.
Ava drew an arrow for 8 near the middle of the line. Is Ava right? Tell a grown-up why. Then draw an arrow where 8 goes.
Estimate. Then tell a grown-up how you know.
Is arrow A closer to 0 or to 100? What number is it pointing to?
Answers
Part 1 · 10s on the line
- 1a
- 20, 50, 70
- 1b
- 30, 60, 90
- 1c
- 40, 50, 60, 70
- 2a
- A = 40; B = 80
- 2b
- A = 10; B = 60; C = 90
Part 2 · 10s and 1s
- 1a
- 32, 35, 39
- 1b
- 61, 63, 68
- 2a
- A = 72; B = 76
- 2b
- A = 17; B = 26; C = 44
- 2c
- A = 64; B = 91
- 3
- 27, 34
Part 3 · What is each step worth?
- 1a
- 4, 8, 16
- 1b
- 15, 35, 45
- 1c
- 10, 40, 80
- 2a
- 2
- 2b
- 5
- 2c
- 10
- 3a
- A = 6; B = 14
- 3b
- A = 25; B = 45
Part 4 · Estimate the arrow
- 1a
- A ≈ 25 (any number from 19 to 31); B ≈ 80 (any number from 74 to 86)
- 1b
- A ≈ 15 (any number from 10 to 20); B ≈ 55 (any number from 51 to 60)
- 1c
- A ≈ 7 (any number from 5 to 9); B ≈ 16 (any number from 14 to 18)
- 1d
- A ≈ 10 (any number from 7 to 13); B ≈ 35 (any number from 31 to 39)
Part 5 · Mark the number
- 1a
- 12 (between 10 and 20), 75 (between 70 and 80)
- 1b
- 40 (less than halfway), 95 (between 90 and 100)
- 1c
- 4 (between 0 and 10), 13 (between 10 and 20)
- 1d
- 20 (less than halfway), 45 (between 40 and 50)
Part 6 · Think about it
- 1a
- No. Each interval is worth 10, not 1. Count in 10s: 10, 20, 30, 40, 50, 60. Arrow A points to 60.
- 1b
- No. Halfway is 50, and 8 is much less than 50. 8 goes close to 0.
- 2
- Closer to 100. It is more than halfway, so it is more than 50. About 65 — any number from 59 to 71 is a good estimate.