Tom counted the number of cards in his collection for 10 weeks by week 5 he had collected 12 cards this graph shows this information how many weeks did it take to have 15 cards collected

The correct answer is 8 weeks, because on the chart, where you see cards collected, as you move from 15, and get to the dot then move from the dot, you see 8, so 8 weeks.

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.

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step-by-step explanation: