What is the least number of quarters, dimes, nickels and pennies needed to be able to make every value from 1 cent to 1 dollar?

  {3 quarters, 1 dime, 2 nickels, 5 pennies}  or  

  {3 quarters, 2 dimes, 1 nickel, 5 pennies}

Step-by-step explanation:

You need change for a nickel, so 5 pennies.

You need change for a dime, so 1 more nickel.

You need change for a quarter, so a dime and a nickel, or two dimes more.

You need change for $1, so 3 more quarters.

You need a minimum of 11 coins. You can use 2 nickels and a dime, or 2 dimes and a nickel to get the values between 15¢ and 25¢. The latter gives you the ability to continue up to $1.05.

  see above for the possible lists

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.