The seller wants to arrange the shoes in a rack such that the number of rows equals the number of columns. This means the total number of shoes should be a perfect square number.
Step 1: Identify the perfect squares near 1000
- $31^2 = 961$ (less than 1000)
- $32^2 = 1024$ (just above 1000)
Step 2: Calculate additional shoes needed
To have a perfect square, the seller needs to have 1024 shoes.
Additional shoes required = $1024 - 1000 = 24$
Step 3: Conclusion
So, the minimum number of shoes he needs more is 24.