Question

How do you add and multiply sig figs without a calculator? What are the rules?

Answer 1

add/subtract sig figs:

just add/subtract normally WITHOUT rounding off. Then, once you get the final answer, then you round off. In rounding off, you follow the number of LEAST decimal places.

For example:

1.234567 + 9.8765

1.234567 has 7 decimal places
9.8765 has 4 decimal places

therefore, the sum should have 4 decimal places

Answer 2

multiplying/dividing sig figs

just multiply/divide WITHOUT rounding off. Then, once you get the final answer, then you round off. In rounding off, you follow the number of LEAST sig figs.

For example:

1.234567 * 9.8765

1.234567 has 8 sig figs
9.8765 has 5 sig figs

therefore, the product should have 5 sig figs

Answer 3

does that help?

Answer 4

Yup, no rules in adding and subtracting?

Answer 5

Oops didn't see first post

Answer 6

as for doing it without any calculators...it's virtually impossible

Answer 7

you can probably get away with doing add/subtract...but you can't multiply/divide without calculators