Subtraction Level 9: 2d - 2d (any). borrow-window subtraction. 1. Release tens72 - 371. Release tensRelease one digit; only borrow stays active.72minus377 - 3 - 1 = 3answer strip3Pay right borrow; release 3: 7 - 3 - 1 = 3.2. Release ones2. Release ones72minus3712 - 7 = 5answer strip35Borrow 10; release 5: 12 - 7 = 5.3. Read answer3. Read answerDrop finished digits; borrow is gone.3 | 5 -> 35answer 35Read 3 | 5 as 35; borrow is gone.
