Use all ten digits from 0 to 9 only once. Do not use 0 in either the milions or thousandths places. What is the greatest number less than 5 million?
Hey! 5 million only has 7 digits. How are we going to use all digits 0-9?
To find the greatest number less than 5 million using all ten digits from 0 to 9 only once, we need to arrange the digits in descending order, starting from the leftmost digit.
Step 1: Exclude the digit 0 from the millions and thousandths places.
Step 2: We have 9 digits left (from 1 to 9) to arrange in the remaining spaces.
Step 3: Start from the leftmost position, which is the millions place, and choose the largest digit available, which is 9. Place it in the millions place.
Step 4: Move to the next available position, which is the hundred thousands place. Choose the next largest digit from the remaining digits, which is 8, and place it in the hundred thousands place.
Step 5: Continue this process for the remaining positions, always choosing the largest available digit.
Step 6: The final arrangement will be the greatest number less than 5 million using all ten digits exactly once.
So, the greatest number less than 5 million using all ten digits from 0 to 9 only once is 9,876,543.