Rounding Significant Figures Demonstration This resource provides animated

Rounding – Significant Figures – Demonstration This resource provides animated demonstrations of the mathematical method. Check animations and delete slides not needed for your class.

Which of these might you expect to hear? What might you hear instead? I ran 13. 5627 km today! There are 19, 482 people in my city. I’m 15 years, 9 months, 2 weeks, 3 days and 7 hours old. 20 million, 220 thousand, 5 hundred and sixteen people watched the football on Saturday. I make sure to drink 4. 482 litres of water every day!

To make communication easier we often want to round numbers. There are 19, 482 people in my city. Which digits in this number can we replace with 0 s and still understand the approximate value? 19, 482 10, 000 19, 400 Which rounded numbers do you think are fair representations?

We can round numbers according to significant (important) figures. Every digit after the first non-zero digit is significant. 2 nd significant figure 3 rd significant figure 1 st significant figure 2863 0. 0046836 1 st significant figure 2 nd significant figure 3 rd significant figure

DEMO Rounding using Significant Figures. Round this number to 1 significant figure. Stay or round up? CHECK 525 500 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 1 significant figure. Stay or round up? CHECK 658 700 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 1 significant figure. Stay or round up? CHECK 52613 50000 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 1 significant figure. Stay or round up? CHECK 0. 0463 0. 05 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 2 significant figures. Stay or round up? CHECK 252 250 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 2 significant figures. Stay or round up? CHECK 4953 5000 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 2 significant figures. Stay or round up? CHECK 72641 73000 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 2 significant figures. Stay or round up? CHECK 0. 005277 0. 0053 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 3 significant figures. Stay or round up? CHECK 8205 8210 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 3 significant figures. Stay or round up? CHECK 60559 60600 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 3 significant figures. Stay or round up? CHECK 1. 473 1. 47 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 3 significant figures. Stay or round up? CHECK 0. 408522 0. 409 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros.

DEMO Rounding using Significant Figures. Round this number to 2 significant figures. Stay or round up? CHECK 4953 5000 Round these numbers to 1 significant figure. 6722 7000 541 500 Round these numbers to 2 significant figures. 6843 6800 34637 35000 Round these numbers to 3 significant figures. 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros. 35268 35300 67952 68000

DEMO Rounding using Significant Figures. Round this number to 2 significant figures. Stay or round up? CHECK 4953 5000 Round these numbers to 1 significant figure. 5. 42 5 7. 501 8 Round these numbers to 2 significant figures. 3. 635 3. 7 0. 0482 0. 048 Round these numbers to 3 significant figures. 1) ‘Cut’ the number. 2) Use the first cut digit to check whether to round UP. (Remember: a 5 means the last digit is rounded up) 3) If necessary complete the number with zeros. 0. 58251 0. 3065 0. 583 0. 307

DEMO Rounding using Significant Figures. Round this number to 2 significant figures. Complete the tables. 1 sf Stay or round up? CHECK 448 4953 6053 5000 82854 355 1 sf 5945 3. 068 0. 05592 0. 40528 2 sf 3 sf

DEMO Rounding using Significant Figures. Round this number to 2 significant figures. Complete the tables. 1 sf 2 sf 448 400 450 4953 6000 6100 355 400 360 5000 82854 80000 83000 Stay or round up? CHECK 1 sf 5945 3. 068 0. 05592 0. 40528 2 sf 3 sf

DEMO Rounding using Significant Figures. Round this number to 2 significant figures. Complete the tables. 1 sf 2 sf 448 400 450 4953 6000 6100 355 400 360 5000 82854 80000 83000 Stay or round up? CHECK 1 sf 2 sf 3 sf 5945 6000 5950 3. 068 3 3. 1 3. 07 0. 05592 0. 06 0. 0559 0. 40528 0. 41 0. 405

Questions? Comments? Suggestions? …or have you found a mistake!? Any feedback would be appreciated . Please feel free to email: tom@goteachmaths. co. uk