I am supposed to add up these numbers, using the significant digits rules.

Question

150
76.9
209
.036

I got 435.936. Following the sig. digs. rules, it would be 435.9, right? How does this then equal 440 as my science books says? Thank you so much.

Answer 1

The lowest sig fig in all the number you added was 2. So you should round your total which is 435.936 so you can get 2 sig figs in your answer. 440 has 2 sig figs.

Answer 2

Chopsticks is almost right. The least sig digit is the tens (150) so nothing past that makes any sense.

440