Practice!

Sample Problem

By using all of the digits 8, 5, 1, 2 and 4 exactly once,

(1) What's the largest 5-digit number you can make?

(2) What's the smallest 5-digit number you can make?

(3) What's the largest 5-digit odd number you can make?

(4) What's the smallest 5-digit even number you can make?

Solution

(1) The digits should be at a descending order from ten thousands place to ones place. So the answer is 85,421.

(2) The digits should be at an ascending order from ten thousands place to ones place. So the answer is 12,458.

(3) The digits should be at a descending order from ten thousands place to ones place based on that the digit 1 should at the ones place. So the answer is 85,421.

(4) The digits should be at an ascending order from ten thousands place to ones place based on that the digit 8 should at the ones place. So the answer is 12,458.