Not one of these activities costs anything, and not one of them needs a screen. All of them work on something real, and the child never has to know it is "learning".
1. The sorting bowl
Tip buttons, bottle tops, blocks or clean pegs into a bowl. Ask your child to sort: first by colour, then by size, then by shape. Then ask which group has the most.
This is Exploring Mathematics in its simplest form. Sorting, classifying and comparing come long before numbers, and they are the thinking that number sense is built on.
2. Cook together
Let them pour, mix, tip and count. Two cups of flour. Three eggs. Wait fifteen minutes. Kitchen work is full of measuring, sequence and patience, and it happens without anyone having to call it a lesson.
The fine muscles get work too: stirring, pinching, and pushing a knife through soft food under supervision.
3. The story you make yourselves
Start with one sentence. "Once there was a dog who could not bark." Let your child give the next sentence. Take turns until the story is finished, however ridiculous it gets.
This builds vocabulary, sentence structure and the understanding that a story has a beginning, middle and end. This is Communication, and it is the best preparation for reading there is.
4. Outside, with nothing
Hand over a bucket and let them collect: ten pebbles, something soft, something rough, something green. Then talk about what they found and how it feels.
Sensory experience is part of how young children learn. Different surfaces under hands and feet build balance, spatial awareness and vocabulary, all at once.
5. The tidy-up race
Set a timer for five minutes and tidy up together. Not as punishment, as a game.
This works on self-regulation, the same skill teachers name first when they talk about school readiness. A child who can start, keep going and finish is a child who can work in a class.
The one rule
Do not turn it into a test. If your child wants to stop halfway and do something else, that is fine. The goal is not to complete a task, it is to be together and keep the brain busy.