Write a real world problem that can be represented by the equation 3/4c=21

There are 21 books in a table if the number of books is 3/4th of the cost of each book then what is the cost of each book.

Solution :

Let c represents the cost of each book,

Also, the number of books = 21

According to the question,

3/4th of the cost of each book = total number of books

Which is the required equation.

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.