Significant Figures Significant figures are those numbers considered

Significant Figures Significant figures are those numbers considered to be important in value All non-zero digits are significant Zeros are NOT always significant

Significant Figures The first significant figure is always the first non-zero digit you come across (from left to right)

To Round to Significant Figures • Identify the significant figure • Look at the number next to it • Round up or down • All the numbers AFTER will become ZERO

There were 64, 492 people at a football match Round 64, 492 to 1 significant figure Round 64, 492 to 2 significant figures Round 64, 492 to 3 significant figures Round 64, 492 to 4 significant figures 60, 000 64, 500 64, 490

• Rounding to 1 s. f. means in the answer we should have 1 significant figure • Rounding to 2 s. f. means in the answer we should have 2 significant figures • Rounding to 3 s. f. means in the answer we should have 3 significant figures

Round to 1 s. f. 43 07 08 50 03 07 Look at the next number It’s more than 4 so we round up!

Round to 3 s. f. 3 7 8 04 03 07 Look at the next number It’s less than 5 so we round down!

Round to 2 s. f. 0. 0 0 2 98 9 Look at the next number It’s more than 4 so we round up!

Round to 3 s. f. 0. 0 0 2 0 98 7 Look at the next number It’s more than 4 so we round up!

Rounding to significant figures Complete this table: to 1 s. f. 6. 3528 34. 026 0. 005708 150. 932 0. 0000783 5 850951 1624564 6446767 to 2 s. f. to 3 s. f.

Rounding to significant figures Complete this table: to 1 s. f. 6 30 0. 006 200 to 2 s. f. 6. 4 34 0. 0057 150 to 3 s. f. 6. 35 34. 0 0. 00571 151 6. 3528 34. 026 0. 005708 150. 932 0. 0000783 0. 00008 0. 0000784 5 850 951 900 000 851 000 1 624 564 2 000 1 600 000 1 620 000 6 446 767 6 000 6 400 000 6 450 000

Homework Pg _____ Exercise 1 G No. s 38 - 47