Q:

# How many combinations of numbers can be made from four digits from 0000 to 9999?

A:

10,000 numbers can be made from combinations of four digits from 0 to 9. The formula for counting the number of combinations is 10^4, or 10 x 10 x 10 x 10.

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Only two numbers are required to figure out how many digits combinations are possible. First, calculate the number of places for digits, which, in this case, is four. Second, calculate the number of choices of digits, which, in this case, is 10. Since digits can be repeated in a combination, each of the four places for digits has 10 digit options: 10 choices for the first place, 10 for the second and so on. The total number of combinations is thus 10 x 10 x 10 x 10.

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## Related Questions

• A:

A number is divisible by 9 if and only if the sum of its digits is divisible by 9. If a number is divisible by 9, it is also divisible by 3 because 9 is a dividend of 3.

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• A:

In mathematics, expanded form is a method of representing a number through an addition statement by totaling the values of its digits. For example, the number 3,745 can be written in expanded form as 3,000 + 700 + 40 + 5. A multiplication statement can also be used in expanded form.

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To tell if a number is evenly divisible by three, add all the digits in it until you arrive at a single digit. For instance, the number 9234 adds up to 18, which adds up to nine. Nine is evenly divisible by three, so 9234 is evenly divisible by three.