Understanding the Rules of Significant Figures & Digits

Imagine you’re a detective looking for clues. In math and science, significant figures (or sig figs) are the important clues in a number that tell you how precise that number is. They’re like the juicy details that make a story accurate and reliable.

Here’s how it works: all non-zero numbers (1-9) are always significant because they’re part of the story. Zeroes can be trickier—they’re like sneaky spies. If a zero is between two significant digits, it’s important (like the zero in 105). Leading zeroes (those before any non-zero digits) are just placeholders and aren’t significant (like in 0.0025). Trailing zeroes (those after a decimal point and a non-zero digit) are significant because they show precision (like in 2.300).

When doing math with sig figs, you have to play by the rules. For multiplication and division, your answer should have as many significant figures as the number with the fewest sig figs in the problem. For addition and subtraction, your answer should match the least number of decimal places in the problem.

Sig figs matter because they help scientists and engineers communicate how precise their measurements are. It’s like saying, “Hey, I measured this really carefully!” So, next time you’re solving a math problem or working on a science experiment, remember the rules of significant figures—they’re the key to precision and accuracy!

[udlgdvx]

Hello,
My name is Sheila. I saw two of your tutor classes since I started doing my GED test. So yesterday was the last day to take my test and I watch your lessons for over two hours. Something Klick that no one else could do. Long story short thank you . I went in yesterday remembering everything you said and I'm proud to say I'm a GED graduate. Thank you.

[yemjxbq]

I learned about significant figures in chemistry.

[HaldaneSmith]

1.001 has 4 significant digits, but 0.999 only has 3. There's obviously some approximation using rules of thumb going on here.