This week I have learned about scientific notation I think it’s quite easy and useful when we see a question 5 times 10^6  and we need to solve it in a quick way. instead of writing out the whole formula we can just move 6 units backward from 5, then we will get 5000000. same as before when we see a question 9 times 10^-9 we can just move nine units starting from 4 then we will get the answer 0.000000009.