Applying the rules of significant figures to calculations

[AznBoi]

I have a question about applying the rules of significant figures to calculations. Should one apply the rules to everyday calculations? I don't know if it will benefit me in the long run to count the number of sig/decimal places in numbers in the simplest calculations. If I major in engineering/physics/math, will I need to use sig figures everyday of my life or what? Do you need to use significant figures in chemistry? physics? everything related to math and calculations? thanks.

 

[AngeloG]

In mathematics it's ideal to get exact answers, and you should be.

Significant figures are useful in real life for chemistry and physics. But you carry out all your calculations until the very end. Then use your significant figures.

It's just telling you your accuracy, if you have a meter stick and tried to measure to the micrometer. It's not going to happen, it's purely guessing up to a certain point and anything after won't matter.

If you had a scale that only read to 2 decimal places, you can get a number with decimal places after calculations. But you're only as accurate as your equipment, so you'd count to two decimal places in the end.