Answer :

you can add 5 because 24+5= 29 and still being divisible by 5. if you add six you need to regroup 

Answer: There are 5 counters that can be added without having to regroup.

Step-by-step explanation:

Since we have given that

Number of counters = 24

We need to add without having to regroup.

It means that we should make it a prime number which does not get divided by any other number except 1 and itself.

so, After 24, there is other numbers that has chances are as follows:

25,26,27,28,29......

But except 29 all the other number can be regroup as they are composite numbers.

But 29 is the nearest prime number after 24.

So, 24+5=29.

Hence, there are 5 counters that can be added without having to regroup.