1. A lesson on significant figuresM A T H S
MIXED STARTER
Write the first five prime numbers.
Round to 2d.p.
Write the HCF of 10 and 15
John has £4 to spend at the newsagent. He spends 30% of his money on sweets and 60% of the remainder on comics. How much does John have left?
A lesson on significant figures
Write the LCM of 3 and 4
Find the product of prime factors for 18.
LO: To round values to a given significant figure

2. Rounding to significant figures A lesson on significant figures
Thursday, 03 May 2018
Rounding to significant figures
Core: will be able to write numbers using words and understand the value of each digit
Challenge: will be able to round to significant figures
Aspire: to be able to describe the difference between rounding and rounding to significant figures
Vivo Star: Understand the importance of rounding to significant figures
Key words – tenths, hundredths, figures, value
A lesson on significant figures
LO: To round values to a given significant figure

3. A Significant figures A lesson on significant figures Round 291.57 toM A T H S
ACQUIRE FLUENCY
Rounding decimals
Order the following decimals in ascending order (smallest first)
Round to
To the nearest 100?
to the nearest 10?
to the nearest whole number?
to one decimal place?
(a)
3.3, 0.5, 1.9, 1.7, 2.4
(b)
0.15, 0.35, 0.24, 0.79, 0.55
(c)
5.7, 5.67, 5.689,5.698, 5.69
A lesson on significant figures
Adding and subtracting decimals
(a)
8.0 – 5.6
(b)
8.5 – 7.1
(c)
9.5 – 1.7
LO: To round values to a given significant figure

4. A lesson on significant figuresM A T H S
TALK ABOUT IT
Round the following number to 2 significant figures
492177
Working from the left the 4 and 9 are the first two most significant numbers so we round after these, therefore =
A lesson on significant figures
LO: To round values to a given significant figure

5. A lesson on significant figuresM A T H S
TALK ABOUT IT
You are going to be shown a number of celebrities and how many people follow them on Twitter
You then need to round these to the number of significant figures indicated
The next slide shows you how I would like you to lay out your answers in your book
A lesson on significant figures
LO: To round values to a given significant figure

6. A lesson on significant figuresM A T H S
TALK ABOUT IT
A lesson on significant figures
LO: To round values to a given significant figure

7. A lesson on significant figuresM A T H S
HAVE A GO
Lady Gaga
32,243,526 followers
2 sig figs
4 sig figs
5 sig figs
A lesson on significant figures
LO: To round values to a given significant figure

8. A lesson on significant figuresM A T H S
HAVE A GO
Cristiano Ronaldo
14,960,666 followers
1 sig figs
2 sig figs
6 sig figs
A lesson on significant figures
LO: To round values to a given significant figure

9. A lesson on significant figuresM A T H S
HAVE A GO
Adele
11,001,473 followers
1 sig figs
3 sig figs
6 sig figs
A lesson on significant figures
LO: To round values to a given significant figure

10. A lesson on significant figuresM A T H S
HAVE A GO
Charlie Sheen
8,604,801 followers
1 sig figs
3 sig figs
6 sig figs
A lesson on significant figures
LO: To round values to a given significant figure

11. A lesson on significant figuresM A T H S
HAVE A GO
Dalia Lama
5,763,274 followers
1 sig figs
3 sig figs
6 sig figs
A lesson on significant figures
LO: To round values to a given significant figure

12. A lesson on significant figuresM A T H S
HAVE A GO
David Beckham
508,995 followers
1 sig figs
3 sig figs
5 sig figs
A lesson on significant figures
LO: To round values to a given significant figure

13. S Set Review the lesson SUM IT UPA T H S
SUM IT UP 3
The larger of two square numbers that sum to 97
The sum of the first six prime numbers 6
Round the following to 2 d.p.
(5 marks) 1
(4 marks)
The highest common factor of 80 and 64 4
(2 marks)
Round the following to 2 s.f.
(4 marks) 2 5
The lowest common multiple of 9 and 15
(2 marks)
(3 marks)

14. A lesson on significant figuresM A T H S
SUM IT UP
Main
When you are rounding to decimal places you start counting after the decimal point, but with significant figures you start counting at the first non zero number
4.7
0.058
0.19
540
A lesson on significant figures
LO: To round values to a given significant figure