Worked answers

Significant Figures Examples with Answers

Fast worked examples for the exact numbers students search: 100, 1000, 0.00450, 90.010, and common rounding questions.

How Many Significant Figures Are in 100?

100 has 1 significant figure unless a decimal point or scientific notation is used to show extra precision.

1000 usually has 1 significant figure. Learn why trailing zeros in whole numbers are ambiguous.

0.00450 has 3 significant figures: 4, 5, and the trailing zero after the decimal.

0.00208 has 3 significant figures because the middle zero is between non-zero digits.

90.010 has 5 significant figures. Zeros between non-zero digits and trailing decimal zeros count.

7982 rounded to 2 significant figures is 8.0e+3, which avoids ambiguous trailing zeros.

0.9978 rounded to 2 significant figures is 1.0 because the next digit rounds 0.99 upward.

0.83 rounded to 1 significant figure is 0.8 because the next digit is less than 5.

123.456 rounded to 3 significant figures is 123 because the fourth significant digit is 4.

In scientific notation, significant figures are counted in the coefficient, not in the power of ten.