Find the Missing Number — Post Office — Grade 1

"Some letters, stamps and a parcel were here, this many are left — how many went away?" That is every row of this sheet. The child finds the missing part by counting up from what remains to the starting group, or by recalling the take-away that fits. Working subtraction from the result backward is the Grade 1 step this practises, with the amounts held within twenty so a child can always count to be sure — the pictured post make that check quick and concrete.

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 post.

Children who like post office 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 reptiles and amphibians, or find the missing number with toys. You can also browse every subtraction worksheet or the whole post collection for grade 1 — each sheet prints cleanly in black and white or plays online for free.