Child in blue polos are sitting around a table writing on their notebooks, one is standing up.
Children doing homework assignments while tutor monitors them.
Children can write without doing homework and they don't necessarily need a tutor to monitors them.
The children may doing something else than doing homework assignments, the one standing may not be tutor
A child in blue polos might be in a uniform, but they might be part of the same club.  Writing on their notebooks might be for something besides homework assignments.  The one who is standing up isn't described as being older or in charge, so we don't know that it is a tutor who monitors them.