Find the difference
1. 4-3/5
2.5-4/7
3.6-2/3
4.5-7/8
5.7-2/5​

1) with 3/5 as a fraction one whole number can be written as 5/5

so you could rewrite 4 as 3 and 5/5 now subtract 3/5 and you are left with

3 and 2/5

2) one whole number can be written as 7/7

Now you have 4 and 7/7 minus 4/7 to get 4 and 3/7

Using the same steps for the rest:

3) 5 and 3/3 -2/3 = 5 and 1/3

4) 4 and 8/8 - 7/8 = 4 and 1/8

5) 6 and 5/5 - 2/5 = 6 and 3/5

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.