Question

whats the number of signifcant figures of each one?

2.46 × 2

714.3 - 18.56

29.3 ÷ (284 × 4.2)

485 ÷ 9.231

1.842 + 45.2 + 87.55

15.2 - 2.75 + 16.67

Answer 1

1) do normal math first

2.46 x 2 = 4.92

now the rule is

THE ANSWER CANNOT CONTAIN MORE SIGNIFICANT FIGURES THAN THE NUMBER BEING MULTIPLIED OR DIVIDED WITH THE LEAST NUMBER OF SIGNIFICANT FIGURES.

so the answer should contain 1 signigicant figure

the answer is 5

2)

first do the normal math

714.3 - 18.56 = 695.74

now

the rule is

THE ANSWER CANNOT CONTAIN MORE PLACES AFTER THE DECIMAL POINT THAN THE SMALLEST NUMBER OF DECIMAL PLACES IN THE NUMBERS BEING ADDED OR SUBTRACTED

so

round the answer to 1 decimal point

the answer is 695.7

3)

first do the math in the brackets

284 x 4.2 = 1192.8

using the rule

the answer should contain two significant figures

we get the answer as 1.2 x 10^3

now

29.3 / 1.2x 10^3 = 24.416 x 10-3

using the rule

the answer should contain two significant figures

so

the answer is 24 x 10-3

4)

do the normal math first

485 / 9.231 = 52.54

now

using the rule

THE ANSWER CANNOT CONTAIN MORE SIGNIFICANT FIGURES THAN THE NUMBER BEING MULTIPLIED OR DIVIDED WITH THE LEAST NUMBER OF SIGNIFICANT FIGURES.

so the answer should contain 3 significant figures

so

the answer is 52.5

5) add in normal fashion

1.842 + 45.2 + 87.5 = 134.592

now

the rule is

THE ANSWER CANNOT CONTAIN MORE PLACES AFTER THE DECIMAL POINT THAN THE SMALLEST NUMBER OF DECIMAL PLACES IN THE NUMBERS BEING ADDED OR SUBTRACTED

in the given numbers , the least number after the decimal point is 1

so

the answer should be rounded to 1 decimal point

the answer is 134.6

6)

do the normal math first

15.2 - 2.75 + 16.67 = 29.12

use the rule

THE ANSWER CANNOT CONTAIN MORE PLACES AFTER THE DECIMAL POINT THAN THE SMALLEST NUMBER OF DECIMAL PLACES IN THE NUMBERS BEING ADDED OR SUBTRACTED

now

round the answer to 1 decimal point

so

the answer is 29.1