The tutor has listed down for you correctly.

You need to list down multiples of 7, then add all of the numbers in this list by 1 (because there is a remainder of 1 when we are dividing the seashells into groups of 7).

8, 15, 22, 29, 36, 43, 50, …

You also need to list down multiples of 6. We do not add any number as (there is no seashell remaining after dividing them into groups of 6).

6, 12, 18, 24, 30, 36, 42, …

We then find the common number because we are dealing with the same bag.

So, the least possible number of seashells is 36.

Try number of bags
③, ⑤ , ⑦, ...
⑤×7+1=36 (Ans)

Why only try odd numbers here?
Please try to figure out?

For primary school students, I don’t think it will be easy to realise that they can skip the sequence by using odd numbers only. The standard approach is still to list down all the numbers.

Nevertheless, it will be a good exercise for the student to explore.

Primary learned Even odd number

Supposed it is good to encourage the kids hv a try to further understand the concept and application.... especially based on the real question.

And this is a P6 question, not P4. For P4 students, maybe it's too challenging.

Definitely list is a more common way......