scientific notation is a x 10^b where a is a number or decimal number such that the absolute value of a is greater than or equal to one and less than ten or, 1 |a| < 10. b is the power of 10 required so that the scientific notation is mathematically equivalent to the original number.
For 2 number x1 and x2:
x1 = a1 × 10b1
x2 = a2 × 10b2
x1 + x2 = a1 × 10b1 + a2 × 10b2
x1 - x2 = a1 × 10b1 - a2 × 10b2
x1 × x2 = a1a2 × 10b1+b2
x1 / x2 = (a1/a2) × 10b1-b2