Question

practice: perform the calculations below. round to the correct number of significant figures. a) 12500×84×1.27 = b) 0.0412×8905÷5.8 = c) 18.9 + 2.51−8.0057 = d) 980591−1250−85424.5 =

Explanation:

Step1: Calculate 12500×84×1.27

First, 12500×84 = 1050000, then 1050000×1.27=1333500. Since 84 has 2 significant - figures, we round 1333500 to 2 significant - figures, getting 1.3×10^6.

Step2: Calculate 0.0412×8905÷5.8

0.0412×8905 = 366.886, then 366.886÷5.8≈63.2562. Since 5.8 has 2 significant - figures, we round to 2 significant - figures, getting 63.

Step3: Calculate 18.9 + 2.51−8.0057

18.9+2.51 = 21.41, then 21.41−8.0057 = 13.4043. Since 18.9 has 3 significant - figures and we are doing addition and subtraction, we round to one decimal place, getting 13.4.

Step4: Calculate 980591−1250−85424.5

980591−1250 = 979341, then 979341−85424.5 = 893916.5. Since 980591 is the least precise value among the numbers in the subtraction (no decimal places), we round to no decimal places, getting 893917.

Answer:

a) 1.3×10^6
b) 63
c) 13.4
d) 893917