Give your 12 year-old a step up on his friends. Let him or her grok negative addition and subtraction! Then, when they get a little older and learn Rust programming, they can tweak this to do whatever new math that needs practice!
Runs in terminal mode (run -> cmd, powershell, bash)
Written in Rust for blazing speed, cross platform, and reliablility.
Demonstration: Control-C to end. (like it was meant to be.)
$> target/debug/mathdrill.exe
1: 9 - (-6) = 15
Correct
2: 4 - (-9) = -6
= 13
3: 1 - 7 = -6
Correct
4: -1 - (-4) = -5
= 3
5: 6 - (-2) = 4
= 8
6: 6 - 7 = ^C
Send me your updates/pull request! (or let your 13 year-old do it as their first contribution to open source!)