+23247 To subtract, get both numbers to have the same (smaller) exponential form.
6.58 x 10^21 = 65.8 x 10^20
65.8 x 10^20 - 7.08 x 10^20 = (65.8 - 7.08) x 10^20 = 58.72 x 10^20 = 5.872 x 10^21
But, this is too precise for the numbers that you were given; so round to get: 5.87 x 10^21
+23247 To subtract, get both numbers to have the same (smaller) exponential form.
6.58 x 10^21 = 65.8 x 10^20
65.8 x 10^20 - 7.08 x 10^20 = (65.8 - 7.08) x 10^20 = 58.72 x 10^20 = 5.872 x 10^21
But, this is too precise for the numbers that you were given; so round to get: 5.87 x 10^21
