1. MNU 3-01a 5-Jun-16Created by Mr. Lafferty Maths Dept. Decimals www.mathsrevision.com Rounding Decimal Places Significant Figures Estimating

2. MNU 3-01a 5-Jun-16Created by Mr. Lafferty Maths Dept. Starter Questions Starter Questions www.mathsrevision.com The answer to the question is 60 Write down as many questions as you can

3. MNU 3-01a 5-Jun-16Created by Mr. Lafferty Maths Dept. www.mathsrevision.com Learning Intention Success Criteria 1. We are learning to round to any number of decimal places. 1. Use previous knowledge to help round to any number of decimal places. Rounding Rounding to Any Number of Decimal Places

4. 5-Jun-16Created by Mr. Lafferty Maths Dept. www.mathsrevision.com Rounding Rounding to Any Number of Decimal Places When rounding to : 1 decimal place look at 2 nd decimal figuree.g. 2.46 e.g. 6.456 e.g. 3.7846 e.g. 13.1146 2 decimal place look at 3 rd decimal figure 3 decimal place look at 4 th decimal figure 4 decimal place look at 5 th decimal figure MNU 3-01a

5. 5-Jun-16Created by Mr. Lafferty Maths Dept. www.mathsrevision.com Rounding Rounding to Any Number of Decimal Places Example : Rounded to 1 decimal place, the number is4.3 4.26 4.262 4.2616 Rounded to 2 decimal place, the number is Rounded to 3 decimal place, the number is Rounded to 4 decimal place, the number is MNU 3-01a

6. 5-Jun-16Created by Mr. Lafferty Maths Dept. www.mathsrevision.com Rounding Rounding to Any Number of Decimal Places Example : Use your calculator to find the answers to 62.73 Round your answers to 2 decimal places. MNU 3-01a 134.59 4.29

7. 5-Jun-16Created by Mr. Lafferty Maths Dept. Now try TJ3a Ex 1 Ch1 (page 7) www.mathsrevision.com Rounding Rounding to Any Number of Decimal Places MNU 3-01a

8. 5-Jun-16Created by Mr. Lafferty Maths Dept. Starter Questions www.mathsrevision.com

9. MNU 3-01a 5-Jun-16Created by Mr. Lafferty Maths Dept. Learning Intention Success Criteria 1.Understand what the term significant figure means. 1.We are learning about the term significant figure. 2.Apply knowledge to problems. www.mathsrevision.com Significant Numbers

10. 5-Jun-16Created by Mr. Lafferty Maths Dept. www.mathsrevision.com Significant Numbers In mathematics a figure or digit is significant if it gives an idea of both: (i)Quantity (ii)Accuracy IMPORTANT : If zero’s are employed just to position the decimal point then they are considered NOT significant. e.g. Has 3 significant figures. 506 cm 50.6 cm 0.506 cm 0.00506 cm Has 3 significant figures. MNU 3-03a

11. 5-Jun-16Created by Mr. Lafferty Maths Dept. www.mathsrevision.com Significant Figures Rounding 0.001090 To the left of the number Middle of the number To the right of the number Not Significant Always Significant MNU 3-01a

12. 5-Jun-16Created by Mr. Lafferty Maths Dept. www.mathsrevision.com Example : How many significant figure for each number. 3 The height of toy is 1.309 metres MNU 3-01a 1 3 Significant Figures There are 500 pennies in £5. There are 800 pupils in St. Ninian’s. There are 360 o in a circle. 4 A strand of hair is 0.040mm wide. 2

13. 5-Jun-16Created by Mr. Lafferty Maths Dept. Now try TJ3a Ex 2 Ch1 (page 9) www.mathsrevision.com Rounding Rounding to Any Number of Decimal Places MNU 3-01a

14. 5-Jun-16Created by Mr. Lafferty Maths Dept. Starter Questions Starter Questions www.mathsrevision.com 42 o

15. MNU 3-01a 5-Jun-16Created by Mr. Lafferty Maths Dept. www.mathsrevision.com Learning Intention Success Criteria 1. We are learning how to estimate an answer using significant figures. Estimating 2. Estimate the answer to a calculation using significant figures. Using Sig. Fig. to Estimate Answers

16. MNU 3-01a 5-Jun-16Created by Mr. Lafferty Maths Dept. www.mathsrevision.com It is very important when solving problems that we have a rough idea of the answer we are expecting. Using Sig. Fig. to Estimate Answers Example : Mentally estimate the answer to 42 x 49 by rounding each number to 1 sig. fig. first. 40 x 50 =400 x 5 =2000 Estimating

17. MNU 3-01a 5-Jun-16Created by Mr. Lafferty Maths Dept. www.mathsrevision.com Example : Mentally estimate the answer to 104 x 19 by rounding each number to 1 sig. fig. first. 100 x 20 =1000 x 2 =2000 Example : Mentally estimate the answer to 878 ÷ 27 by rounding each number to 1 sig. fig. first. 900 ÷ 30 =90 ÷ 3 =30 Estimating Using Sig. Fig. to Estimate Answers

18. 5-Jun-16Created by Mr. Lafferty Maths Dept. Now try TJ3a Ex 3 Ch1 (page 11) www.mathsrevision.com Estimating MNU 3-01a Using Sig. Fig. to Estimate Answers