# Thread: scientific notation and significant figures ( i don't have a lot of time please! )

1. ## scientific notation and significant figures ( i don't have a lot of time please! )

This was In my chemistry homework but i cant figure out if im doing it right because there is nothing like it in the book.

Round the following numbers to the specified significant figures and write in scientific notation.
a. 0.99692 x 10-2 to 3 sig. fig.
b. 0.03944498 to 2 sig. fig.
c. 136.050 to 3 sig fig.
d. 102.50 x 10-13 to 2 sig fig.
e. 0.0020050001 to 3 sig. fig.
f. 0.4975000 to 3 sig fig.

What i got
a.9.97 x 10^-3
b. 4.0 x 10^-2
c. 1.360 x 10^2
d. 1.02 x 10^-15
e. 2.00 x 10^-3
f. 4.98 x 10^-1

there is also a rule we follow that says "if the next digit is 5 or followed by only zeros then a)if the number before is even then retain the previous digit b)if its odd then increase previous digit by one"

ex 1.27500 =1.28
ex 1.28500 =1.28
ex 1.9950 = 2.00
ex 19850 = 1.98

2. Originally Posted by Dray
This was In my chemistry homework but i cant figure out if im doing it right because there is nothing like it in the book.

Round the following numbers to the specified significant figures and write in scientific notation.
a. 0.99692 x 10-2 to 3 sig. fig.
b. 0.03944498 to 2 sig. fig.
c. 136.050 to 3 sig fig.
d. 102.50 x 10-13 to 2 sig fig.
e. 0.0020050001 to 3 sig. fig.
f. 0.4975000 to 3 sig fig.

What i got
a.9.97 x 10^-3
b. 4.0 x 10^-2 ← 3.9 * 10-2
c. 1.360 x 10^2 ← 1.36 * 102
d. 1.02 x 10^-15← 1.0 * 10-15
e. 2.00 x 10^-3
f. 4.98 x 10^-1

there is also a rule we follow that says "if the next digit is 5 or followed by only zeros then a)if the number before is even then retain the previous digit b)if its odd then increase previous digit by one"

ex 1.27500 =1.28
ex 1.28500 =1.28
ex 1.9950 = 2.00
ex 19850 = 1.98

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