Odd and even is one of those number concepts that sounds tiny and turns out to take a while. A small child in our house had been comfortably counting to a hundred for months and could read most two-digit numbers on sight, and the day I asked whether seventeen was odd or even, the question landed like a curveball. So I built a small magnetic fishing game with a fish for each number from one to twenty, two sorting bowls, and one rule: catch a fish, read its number, drop it in the right bowl. It is a quiet, repeatable activity that takes the abstract idea and makes it physical. Ages 4 to 7.
What you need
- A sheet of colored cardstock and a permanent marker, for making the fish.
- Twenty small paper-fastener brads (the split-pin kind with a flat round head and two prongs that fold flat). One per fish. These do two jobs: they look like a fish eye, and the metal head is what the magnet sticks to.
- A magnetic fishing rod. A small wooden dowel or chopstick with a length of string and a small magnet tied on the end. If you have a children’s magnetic fishing toy already, that works too.
- Three small bowls. Plastic mixing bowls or party-size cocktail bowls are the right size.
- Pom poms or small filler to bury the fish in. The filler is mostly visual but it slows the fishing down enough that a child can read each number properly.
Making the fish
Draw twenty fish onto the cardstock, roughly the size of a credit card, and cut them out. Simple side-on shapes work best: a rounded body with a triangular tail. Write a different number from one to twenty on each fish with the marker.
Push a paper-fastener brad through the head of each fish. The flat round head sits on the front of the fish as the eye. Fold the two prongs flat against the back. That is the magnet point. With the brad in place, add a small curved mouth in front of the eye with the marker so the fish actually looks like a fish.
If you want a longer game, make two of each number. It doubles the runtime and lets a child see the same number land in the same bowl twice in a row, which is the moment the pattern clicks.
Setting up the bowls
Three bowls in a row. The middle bowl is the “lake”: fill it with pom poms and tuck the fish in among them, mostly facing up so the brads are catchable. The bowl on the left gets a hand-written “ODD” label. The bowl on the right gets “EVEN”.
How it goes
The rule is one fish at a time. Lower the magnet into the lake bowl, let it click onto a brad, lift the fish out, read the number aloud, decide odd or even, and drop the fish into the matching bowl.
The first few catches will probably be guesses. That is fine. The shortcut to teach is the last-digit rule: if the number ends in 0, 2, 4, 6, or 8, it is even. Anything else is odd. That single rule covers every two-digit number a small child is likely to meet for the next few years, and it is concrete enough to apply to each fish without having to count out anything.
By about the fourth or fifth fish, ours had the rule. The catching slowed down a bit while the deciding caught up. Then the catching sped up again because the answer was suddenly easy.
The quiet fine motor work
The math is the headline, but the fine motor work is the part that earns the activity its place in the rotation. Lowering a rod and a swinging magnet into a bowl of pom poms, hovering the magnet over the right spot, lifting a small cardboard fish out without dropping it back in. The wrist control, the steady hand, the slight pause to let the magnet click. All of it is the same control a child needs for using a spoon, a pencil, and a paintbrush.
When it is done, scoop the fish back into the lake bowl with the pom poms, tip them all in, and the game is ready for next time. Ours stayed out on the table for the better part of a week, with a small child wandering past and catching a few more fish whenever they passed.
For another math game in the same age band, our pirate doubling numbers game uses a similar physical-sorting approach for the harder concept of doubles. And for a quieter sit-down option in the same age band, our free mermaid coloring pages give a child something to color when the bowls go back in the cupboard.