3-Digit Addends: No Shifting 2-92
Use Base 10 discs to model and add 3-digit addends with no regrouping. What's 216+423? Group same units together. Add hundreds. Add tens. Add ones. 200+400 = 600, 10+20 = 30, and 6+3 = 9. Add the 3 partial sums to get the total sum. 216+423 = 600+30+9 = 639. Transition to number bonds and equations.
