Subtract Within 20: With and Without Regrouping

Practice mental subtraction within 20 with two progressive levels:

• Level 1: Simple subtraction (no regrouping), like 17 – 5.
• Level 2: Subtraction with regrouping (borrowing), like 15 – 8.

All problems align with Common Core standard 2.OA.B.2 and include instant feedback. No printing — just free, interactive fluency practice!