It is important for a child to continue maths work throughout long holidays with a combination of workbooks and tutorials
During the long summer holidays (and other such as Easter and Christmas) it is very important for a child to;
A) Work their way through workbooks, and;
B) Have regular tutorials to tackle any questions which could not be solved
The advantage of online tutoring is that a child can have a tutorial no matter where in the world they are, including on holiday. One a week is typically fine, or twice a week for children in UK Year 5 who will return to school and start their 11+ exams in the first week or so of Y6 as they also ramp-up for the Independent School Entrance Exams.
Summer maths camps are of use, but are typically focused on getting as many children to attend as possible which diminishes the value delivered to each child. In addition the homework is generic, whereas the homework from a tutor is targeted.
Workbooks are also of importance, assuming the parents have time to mark all the work and can offer advice on how to solve questions which the child cannot. This becomes more difficult in the first year or so of Secondary School when teenagers are tackling algebra and more advanced trigonometry.
Keep up the workbooks while on holiday and if you are interested please contact me for a free no-commitment tutorial session anywhere in the world: