1+5+4=10 so that's not it. if you meant 154x11=1694 1+6+9+4=20 so that's not it either. By checking manually, it's 209. 19x11=209 2+0+9=11 The way you are d

1+5+4=10 so that's not it. if you meant 154x11=1694 1+6+9+4=20 so that's not it either. By checking manually, it's 209. 19x11=209 2+0+9=11 The way you are doing doesn't seem correct even if what you said it's true, you aren't multiplying by 11. I have no idea what the reasoning to prove the negative would be. I'd be interested to read it, if anyone knows.