What is the least common denominator for the fractions 1/3 and 2/9

the LCD of the two is 9 what you do is this  so 1/3,2/9 is simple its 1/3 2/3 1 then lets try the 2/9 2/9 4/9 6/9 and keep doing that until they both reach the SAME number.

The LCD (Least common denominator) is 9,  

For the denominators (3, 9) the least common multiple (LCM) is 9.

Therefore, the least common denominator (LCD) is 9.

Hope This Helps :D

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.