Decimals & rounding

Decimals are another way to show parts of a whole, using place value after a decimal point — tenths, hundredths, thousandths. Money is written in decimals every day: $4.65 means 4 dollars and 65 cents. Rounding simplifies a number to a given place: look at the next digit — 5 or more rounds up, 4 or less rounds down.

Key terms

Decimal point:

The dot separating whole numbers from parts less than one.

Tenths / hundredths:

Place values for the first and second digits after the decimal point.

Rounding:

Simplifying a number to a given place value.

Questions

1. 1. In $4.65, what does the 6 represent?

   • 6 dollars
   • 6 tenths (60 cents)
   • 6 hundredths (6 cents)
   • 6 cents only

2. 2. Round $23.47 to the nearest dollar.

   • $22
   • $23
   • $24
   • $23.50

3. 3. Which is bigger, 0.5 or 0.25?

   • 0.5
   • 0.25
   • Equal
   • Cannot tell

4. 4. Round 6.7 to the nearest whole number.

   • 6
   • 7
   • 6.5
   • 8

5. 5. What is $5.20 + $2.30?

   • $7.50
   • $7.20
   • $8.50
   • $5.50

6. 6. In 0.83, what does the 8 represent?

   • 8 tenths
   • 8 hundredths
   • 8 ones
   • 8 thousandths

7. 7. Which decimal equals one half?

   • 0.2
   • 0.25
   • 0.5
   • 0.75

8. 8. Round $14.83 to the nearest 10 cents.

   • $14.80
   • $14.90
   • $15.00
   • $14.83

9. 9. What is $10.00 − $3.65?

   • $6.35
   • $7.35
   • $6.45
   • $7.65

10. 10. Order from smallest to largest: 0.4, 0.09, 0.45

    • 0.09, 0.4, 0.45
    • 0.4, 0.09, 0.45
    • 0.45, 0.4, 0.09
    • 0.09, 0.45, 0.4

11. 11. Round 3.148 to two decimal places.

    • 3.14
    • 3.15
    • 3.1
    • 3.2

12. 12. Three items cost $2.50 each. What is the total?

    • $5.00
    • $6.50
    • $7.50
    • $8.50

13. 13. What is 0.6 + 0.35?

    • 0.41
    • 0.95
    • 0.65
    • 0.9

14. 14. You pay with a $20 note for a $13.25 item. What is your change?

    • $6.75
    • $7.25
    • $6.25
    • $7.75

15. 15. A litre of petrol costs $1.87. How much do 4 litres cost, rounded to the nearest 5 cents?

    • $7.45
    • $7.48
    • $7.50
    • $7.40

16. 16. What is $45.90 ÷ 3?

    • $15.00
    • $15.30
    • $16.30
    • $13.30

17. 17. Round 128.456 to one decimal place.

    • 128.4
    • 128.5
    • 128.45
    • 128.46

18. 18. You buy 3 items at $6.85 each and pay with $25. What is your change?

    • $4.45
    • $4.55
    • $5.45
    • $3.45

19. 19. A recipe needs 0.75kg of flour. You have a 2.5kg bag. How much flour is left after making the recipe once?

    • 1.25kg
    • 1.75kg
    • 1.5kg
    • 2.0kg

20. 20. What is 4.2 − 1.65?

    • 2.45
    • 2.55
    • 3.45
    • 2.65

21. 21. A phone bill of $67.849 should be rounded to the nearest cent as:

    • $67.84
    • $67.85
    • $67.80
    • $67.90