You subscribe to m different magazines. your friend subscribes to 2 fewer than you

In order to put a number into scientific notation, you multiply or divide the number by multiples of 10 until your base number is between 1 and 10 then you raise the number to the negative or positive exponent in the amount that you used to multiply or divide the number... Let me show you...

0.000000106 millimeter

Every time you multiply by 10, you move the decimal one place to the right. In this case if you multiply by 10 seven times, the decimal moves 7 places to the right. Now you have

1.06 ... but you can't just change a number so you have to show how your number is equivalent to the original number. You do this with the exponents. If you raise the new number to the -7 exponent, it shows you have to move the decimal 7 places to the left to expand to your original number. So the scientific notation would be...
1.06 × 10^-7

*note- if you move the decimal to the left you would have a positive exponent. If you move it to the right you'll have a negative exponent.