Andrea, Beth, & Cathy's ages are consecutive whole numbers. Andrea is the youngest, and Cathy is the oldest. The sum of their ages is 54. How old is Cathy?

Age of Cathy = 19

Step-by-step explanation:

Find:

Sum of their ages = 54

Assume;

Age of Andrea = x

Age of Beth = x + 1

Age of Cathy = x + 2

Sum of their ages = x + x + 1 + x + 2

54 = 3 x + 3

3 x = 51

x = 17

Age of Cathy = x + 2

Age of Cathy = 17 + 2

Age of Cathy = 19

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.