1. Week 13 Understand and use rounding, estimation and check calculations
Functional MATHS
Week 13
Understand and use rounding, estimation and check calculations

2. FOUR LINES Put 9 dots in a square like this….
Can you go through all 9 dots with four straight
lines?
(you can’t take the pen off the paper)

3. ANSWER

4. Re-cap: What did we do last week?

5. Revision of formulae (tasks 1 & 2)
Re-cap: What we did last week…
Revision of formulae
(tasks 1 & 2)
Calculate substituting letters for numbers
Understand and use simple word formulae
Solve problems by substituting into a formula (to include letters and symbols)

6. Put your name on it please before handing in!
Directed Study

7. What are we going to do today?
Rounding, estimating and checking
Round to 10, 100, 100 and to decimal places
Estimate without using a calculator
Check calculations using reverse methods
Assessment (tasks 1 and 2)

8. ROUNDING
Nearest 10
Nearest 100
Nearest 1000

9. Rounding – to the nearest 10
1 9 5
5 or more?
5 or more?
5 or more? No
Yes
Yes
2 0 0

10. Rounding – to the nearest 100
8 9
5 or more?
5 or more?
5 or more? No
Yes
Yes
1 0 0

11. Rounding – to the nearest 1000
5 or more?
5 or more?
5 or more? No
Yes
Yes

12. ROUNDING
1 decimal place
2 decimal places
e.g. money

13. Rounding to 1 Decimal Place (1DP)
5 or more?
5 or more?
5 or more? No No
Yes
4 . 8
4 . 8
4 . 9
5 or more?
5 or more?
5 or more?
Yes
Yes
Yes
4 . 9
5 . 3
2 . 0

14. Rounding to Decimal Places: 2DP
5 or more?
5 or more?
5 or more? No
Yes
Yes
5 or more?
5 or more?
5 or more? No
Yes
Yes

15. Rounding to Decimal Places
1DP
2DP
3DP
5 or more?
5 or more?
5 or more?
Yes No
Yes
4 . 9
Copy &
complete
this table:
Number
To 1DP
To 2DP
To 3DP
63.5
63.47
63.472
87.7
87.66
87.656
Your Turn
150.0
149.99
3.5
3.54
3.540
0.6
0.60
0.600

16. Estimation
Using rounding to estimate answers

17. Estimation and Rounding
What is… = 79 50 30 + = 80

18. =
179 70
110 + =
180

19. =
278 50
230 + =
280

20. Checking calculations
Estimation
Reverse check

21. Checking calculations
Using estimation or a reverse check

22. Checking calculations
Using estimation or a reverse check

23. Drawing a table

24. Fractions and percentages

25. Mini Assessment Feedback next week!
You now have to the end of the lesson to complete task 1 and task 2.
You are expected to stay for the full time. If you finish the assessment early, use the time wisely to check through your answers.
Feedback next week!

26. Directed study Revise Your targets…
Use Moodle (and suggested internet sites) to revise your targets as it is time to review them over the next couple of weeks
(hint: if you can’t remember them look on pro-portal)!!!