Question

calculation with sig figs video
what does it mean when they say you can only be as precise as your least precise number?
adding and subtracting
rule for adding and subtracting:
problem answer rounded sig fig #
10.21
+1.3
12
+ 2.54
9.2

• 3.36

87.398

• 86.50

Explanation:

Step1: Add 10.21 and 1.3

$10.21 + 1.3=11.51$. The least precise number is 1.3 which is precise to the tenths place. So we round 11.51 to 11.5.

Step2: Add 12 and 2.54

$12+2.54 = 14.54$. The least precise number is 12 which is a whole - number (precise to the ones place). So we round 14.54 to 15.

Step3: Subtract 3.36 from 9.2

$9.2−3.36 = 5.84$. The least precise number is 9.2 which is precise to the tenths place. So we round 5.84 to 5.8.

Step4: Subtract 86.50 from 87.398

$87.398−86.50 = 0.898$. The least precise number is 86.50 which is precise to the hundredths place. So we round 0.898 to 0.90.

Answer:

Problem	Answer	Rounded Sig Fig #
12 + 2.54	14.54	15
9.2 - 3.36	5.84	5.8
87.398 - 86.50	0.898	0.90