Rebecca sold 11 more magazine subscriptions than chad. laura sold 4 more than rebecca. laura sold 45 magazine subscriptions. how many subscriptions did chad sell

If Laura sold 45 and if that is 4 more than Rebecca, Rebecca sold 45 - 4 or 41 subscriptions. If Rebecca sold 11 more than Chad, 41 - 11 is how many Chad sold, which is 30 subscriptions

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.