4,777 km
4 of them.
26.0
8 L
The least number of significant figures in any number of the problem determines the number of significant figures in the answer.
Only three significant digits are correct, because 5.0 contains no digit for hundredths, and such a digit would be required to give four significant digits in the answer. Because 7 + 5 equals exactly 12, a third significant digit is gained for the answer. Note in contrast that the sum of 7.68 and 0.50 would properly contain four significant digits.
12.7
The product is 11 mm
The correct format for an American Express card number, which consists of 15 digits, is XXXX XXXXXX XXXXX.
The sum is: 1333 km
4 of them.
26.0
Four significant digits in 50.00.
5.2
4.0 x 10-2 * 8.1 x 102 = 32.4 2 significant digits, so the answer is 32.
9L
An American Express credit card number is typically 15 digits long and starts with the number 3.
When multiplying numbers with significant digits, count the total number of significant digits in each number being multiplied. The result should have the same number of significant digits as the number with the fewest significant digits. Round the final answer to that number of significant digits.