Start with a decimal number like 7.2 and multiply it with 10^1 = 10
7.2 * 10 = 72
Then multiply 7.2 by 10^2 = 100
7.2*100 = 720
Then 10^3 = 1000
7.2 * 1000 = 7200
Then 10^4 = 10000
7.2 * 10000 = 72000
Each time we add a 0 onto 10 (or 100 or 1000, etc) we add a 0 onto the previous result (72 --> 720 --> 7200, etc)
This is the same as moving the decimal point 1 spot to the right. The exponent over the 10 tells us how many spots to move the decimal
For something like 7.2 * 10^3, we move the decimal point 3 times to the right to end up with 7200
If the exponent over the 10 was negative, then we move the decimal point to the left.