What is the name of the principle which states that students should be neither bored by work that is too simple nor left behind by teaching they cannot understand?

The principle that students should be neither bored by work that is too simple nor left behind by teaching they cannot understand is the problem of the match.

It calls for matching the difficulty of instruction to the learner's present level.

Synaptic plasticity is the brain's capacity to strengthen or weaken connections between neurons.

Seriation is the cognitive ability to arrange items in order by a dimension such as size.

Reverse thinking is working backward from a goal or result rather than matching difficulty.

The problem of the match reflects the idea of pitching learning within the learner's reach, akin to the zone of proximal development.