So we're home-schooling our 6-yr old and she's doing basic addition/subtraction/multiplication/division.. and I wrote a subtraction problem backwards by accident the other day, and I can't figure out how to show her how to solve it.
Any help would be appreciated.
30 - 45
I know it equals -15, and I know why - but I don't know how to explain how to do the math.
30 - 45 ----
borrow one from the 3, it becomes 2, the 0 becomes 10.. 10 - 5 = 5. Then 2 - 4.. what do you do here? I keep getting -2. Which makes the result -25.