Find the Missing Number — Tools — Grade 1

The unknown here is the amount removed, not the answer. A group of hammers, saws and a wrench is pictured, the number left is written, and the child finds how many were taken away to get there. That is change-unknown subtraction — a step beyond plain take-away, because the child reasons about the missing middle. Kept within twenty, it leans on counting up and on knowing which take-away makes the result, and the pictured tools keep that reasoning anchored to something a child can count.

Asking for the taken-away amount rather than the result keeps a child from running a page on autopilot — each row needs real thought about the missing middle. That is precisely why change-unknown problems matter at Grade 1, and why keeping them within twenty is important: the thinking is the work, so the numbers stay small enough to verify by counting the tools.

Children who like tools take to the puzzle of working backward, and it suits a child ready for a little more than plain take-away. When this feels easy, try find the missing number with toys, or find the missing number with fourth of july things. You can also browse every subtraction worksheet or the whole tools collection for grade 1 — each sheet prints cleanly in black and white or plays online for free.