Consider the number 6789. If I switch the digits in the ones and hundreds place, what would be the resulting number?

• A. 6987
• B. 6897
• C. 6789
• D. 6798

Answer: (A)

Swapping the digits in the ones and hundreds places means keep the thousands and tens digits the same, but exchange the digits in the hundreds and ones places.

In 6789, the digits by place value are: thousands 6, hundreds 7, tens 8, ones 9. Swap the hundreds digit 7 with the ones digit 9. Now you have 6 in the thousands place, 9 in the hundreds place, 8 in the tens place, and 7 in the ones place. That gives 6987.

The other options don’t reflect that swap. For example, 6897 keeps the hundreds and tens digits mixed, not swapping hundreds with ones; 6789 is unchanged; 6798 swaps tens and ones, not hundreds and ones.