express the numbers and the answers in exponential numbers and indicate the number of significant numbers?

Question

830, 95.30, 53107

Answer 1

830 has only 2 significant digits (according to the rules, the zero doesn't count unless there are also digits to the right of the decimal point), so it would be 8.3 × 10².

95.30 has 4 significant digits, so it's 9.530 × 10¹.

53107 has 5 sig digs, so it's 5.3107 × 10⁴.