Subtract a 2-digit number from a 2-digit number without regrouping (exchanging/borrowing). May 13, 2025 by Dan
Columnar Addition (up to 3 digits): Add two 2-digit numbers without regrouping (carrying). May 13, 2025 by Dan
Apply known number bonds to 10, 20, and 100 to assist mental addition and subtraction (e.g., 135+7 by thinking 5+7=12). May 13, 2025 by Dan
