This week I learned how to do scientific notation!
It’s used for when you have a number that is much too large or much too small, and you want it to be smaller. (A number like 32400000000 or 0.0000021.) To make the number 32400000000 into a scientific notation you make it 3.24, then put times 10 and then count how many places the decimal must move down to get to the end of the number to make the whole thing a whole number, and make that the exponent on the 10. So in the case of 32400000000 the answer is 3.24 x 
The way you use scientific notations with really small numbers like 0.0000021 is you make that number 2.1, and then put times 10, and then count how many places the decimal must move down to get to the decimal point that was in the original number (0.0…) and make that number the exponent on the 10 BUT make the exponent a negative number. So in the case of 0.0000021, the answer is 2.1 x 