Final answer:
Expression of numbers in scientific notation involves placing the decimal after the first non-zero digit and indicating the power of ten needed to scale the number back to its original value. The number of significant figures is determined by the original numbers in the expression.
Step-by-step explanation:
To successfully express these numbers using scientific notation with the correct number of significant figures, we follow the process demonstrated in this example:
217 ÷ 903: Divide the two numbers normally and then express the result in scientific notation. This gives 0.2403, which in scientific notation becomes 2.403 × 10-1 and has four significant figures.
13.77 + 908.226 + 515: After summing these values, we get 1437.006. In scientific notation, this is 1.437006 × 103 and all seven figures are significant.
255.0 - 99: The answer is 156.0, which, in scientific notation, is 1.560 × 102. It has four significant figures due to the decimal place in the original number.
0.00666 × 321: We get the product as 2.13666, which in scientific notation is 2.13666 × 100. Here we have six significant figures in the result.