Significant Figures Significant figures are those numbers considered to be important in value All non-zero digits are significant Zeros are NOT always significant To compare two numbers you would need the 3 To compare two numbers for 203 the 0 plays an important role

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 60,000 Round 64,492 to 2 significant figures 64,000 Round 64,492 to 3 significant figures 64,500 Round 64,492 to 4 significant figures 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

It’s more than 4 so we round up! Round to 1 s.f. 3 7 8 5 4 3 7 Look at the next number It’s more than 4 so we round up!

It’s less than 5 so we round down! Round to 3 s.f. 3 7 8 4 3 7 Look at the next number It’s less than 5 so we round down!

It’s more than 4 so we round up! Round to 2 s.f. . 2 9 8 9 Look at the next number It’s more than 4 so we round up!

It’s more than 4 so we round up! Round to 3 s.f. . 2 9 8 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. to 2 s.f. to 3 s.f. 6.3528 34.026 0.005708 150.932 0.00007835 850951 1624564 6446767

Rounding to significant figures Complete this table: to 1 s.f. to 2 s.f. to 3 s.f. 6.3528 6 6.4 6.35 34.026 30 34 34.0 0.005708 0.006 0.0057 0.00571 150.932 200 150 151 0.00007835 0.00008 0.000078 0.0000784 850 951 900 000 850 000 851 000 1 624 564 2 000 000 1 600 000 1 620 000 6 446 767 6 000 000 6 400 000 6 450 000

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