Step 4 / 4
Missing number
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Add within 20 · Numbers & Operations
From no-carry to carrying sums, adding three numbers, and missing addends.
This is step 4 of unit 1, “Add within 20”, in Stage 2: Carrying, borrowing and numbers to 100 (ages 8). A round has 10 problems; 90% or better earns three stars. Everything is free with no sign-up, and your stars and XP are saved on this device.