Question

Round off the following numbers to two significant digits.
(a) 7.8361
(b) 85.51
(c) 2.85
(d) 9.865
(e) 4.67
(f) 2.75
(g) 6.750
(h) 490.0
(i) 0.006 070
(j) 648 700
(k) 704
(l) 0.599 0
(m) 435
(n) 0.000 16
(o) 0.032 45
(p) 6 807
(q) 0.000 053
(r) 0.070 40
(s) 68
(t) 0.080 5

Answer 1

someone tell me how to do this

Answer 2

http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch1/sigfigs.html

Answer 3

2 significant digits means x.xx (2 numbers after the decimal point; even if it is a while number).

Simply round from the numbers right to left and stop after the 3rd digit after the decimal place.

Example: rounding 3.7456 would be 3.75

Answer 4

what abt 4 significant digits

Answer 5

Then, you'll need to have 4 digits after the decimal place.

The same would be applied, but if say you need to round the number 5, it would be 5.0000

Significant digits (significant figures) are usually used for noting accuracy.

Answer 6

oh ok thanks

Answer 7

You're Welcome!

Answer 8

do you kno how to do scientific notations as well

Answer 9

if you do, can you show me how please

Answer 10

I do

Answer 11

how do you do it

Answer 12

can you giv me an example

Answer 13

Scientific notation is basically getting a very big (or small) number, starting from the end (if big) or beginning (if small [decimal]), and count the place values from the initial point to a decimal point after the number.

example:
440000
4.4x10^5

Here, you need to put an imaginary decimal point at the end of the number and shift it until you get the number 4.4. Count the place values and that's your x10 exponent.

works the same way in a very small number

0.00002
2.0x10^-5