Year 5 Maths: Ordering Decimals

Understanding Decimals

Hello, Year 5! Today, we are going to learn about ordering decimals. Decimals are numbers that have a whole part and a fractional part, separated by a decimal point. For example, in the number 3.45, 3 is the whole part, and 0.45 is the fractional part.

What Does Ordering Decimals Mean?

Ordering decimals means arranging them from the smallest to the largest or from the largest to the smallest.

Key Rules for Ordering Decimals

1. Compare the Whole Numbers First: Look at the numbers before the decimal point. The bigger whole number is the bigger decimal.
   • Example: 4.2 and 3.9 – Since 4 is greater than 3, 4.2 is bigger!
2. Look at the Decimal Places Next: If the whole numbers are the same, look at the first digit after the decimal point.
   • Example: 2.3 and 2.5 – Since 3 is less than 5, 2.3 is smaller than 2.5.
3. Continue Comparing: If the first decimal digits are the same, look at the next decimal place.
   • Example: 2.45 and 2.4 – Here, 2.4 can be thought of as 2.40. Now compare: 40 is greater than 45, so 2.45 is larger.

Tips and Tricks

• Line Them Up: When comparing decimals, it helps to write them down so the decimal points are lined up vertically. This makes it easier to see which number is larger.
• Use Place Values: Remember that each place after the decimal is worth less than the one before it. For example, tenths (0.1) are larger than hundredths (0.01).
• Zeroes Matter: If a decimal has extra zeroes, it doesn’t change the value. For example, 2.50 and 2.5 are the same!

Visual Example

Let’s say we have the following decimals to order: 1.2, 0.9, 1.05, 1.25.

1. Compare the whole numbers: All have a whole number of 1 or 0.
2. Compare the first digits after the decimal:
   • 1.2 (2)
   • 0.9 (9 – smaller than any starting with 1)
   • 1.05 (0)
   • 1.25 (2)
3. Order them:
   • 0.9 (smallest)
   • 1.05
   • 1.2
   • 1.25 (largest)

So, the order is 0.9, 1.05, 1.2, 1.25.

Practice Questions

Easy Level Questions

1. Order these decimals: 0.5, 0.3, 0.7
2. Which is larger: 1.2 or 1.1?
3. Order these decimals: 2.1, 2.0, 2.2
4. Which is smaller: 0.8 or 0.9?
5. Order these decimals: 3.4, 3.1, 3.3
6. Which is larger: 1.5 or 1.4?
7. Order these decimals: 0.02, 0.01, 0.03
8. Which is smaller: 2.5 or 2.6?
9. Order these decimals: 4.0, 4.1, 4.2
10. Which is larger: 0.5 or 0.4?

Medium Level Questions

11. Order these decimals: 1.25, 1.5, 1.15
12. Which is larger: 2.75 or 2.7?
13. Order these decimals: 0.45, 0.5, 0.48
14. Which is smaller: 3.3 or 3.33?
15. Order these decimals: 0.99, 0.9, 0.999
16. Which is larger: 4.25 or 4.2?
17. Order these decimals: 1.01, 1.001, 1.02
18. Which is smaller: 2.2 or 2.20?
19. Order these decimals: 0.6, 0.06, 0.16
20. Which is larger: 5.5 or 5.55?

Hard Level Questions

21. Order these decimals: 3.49, 3.9, 3.5, 3.45
22. Which is larger: 6.007 or 6.1?
23. Order these decimals: 2.56, 2.5, 2.55, 2.57
24. Which is smaller: 1.234 or 1.243?
25. Order these decimals: 3.141, 3.14, 3.15, 3.1
26. Which is larger: 0.999 or 1.0?
27. Order these decimals: 5.3, 5.30, 5.33, 5.31
28. Which is smaller: 7.2 or 7.20?
29. Order these decimals: 0.007, 0.07, 0.7, 0.07
30. Which is larger: 8.888 or 8.88?

Answers

Easy Level Answers

1. 0.3, 0.5, 0.7
2. 1.2
3. 2.0, 2.1, 2.2
4. 0.8
5. 3.1, 3.3, 3.4
6. 1.5
7. 0.01, 0.02, 0.03
8. 2.5
9. 4.0, 4.1, 4.2
10. 0.5

Medium Level Answers

11. 1.15, 1.25, 1.5
12. 2.75
13. 0.45, 0.48, 0.5
14. 3.3
15. 0.9, 0.99, 0.999
16. 4.25
17. 1.001, 1.01, 1.02
18. 2.2
19. 0.06, 0.16, 0.6
20. 5.55

Hard Level Answers

21. 3.45, 3.49, 3.5, 3.9
22. 6.1
23. 2.5, 2.55, 2.56, 2.57
24. 1.234
25. 3.1, 3.14, 3.141, 3.15
26. 1.0
27. 5.3, 5.30, 5.31, 5.33
28. 7.2
29. 0.007, 0.07, 0.07, 0.7
30. 8.888

Now, go ahead and practice ordering decimals! Remember to use the tips and tricks we’ve learned today. Happy learning!