TenPoundHammer wrote:500-380. Okay, that's 50-38. Can't take away from 0, so borrow the 1. 4 [10] - 38. 10 minus 8 is 2... oh wait, what did I have up there again, a 5 or a 4? Crap, go back. 50-38. 10-8=2, 5-3 is... whoops. Borrowing and carrying ALWAYS trip me up because it's too many numbers to keep track of.
This is why many people recommend not using borrowing and carrying for mental subtraction. Another way to do it is to "add up" to the number. People often do this when making change.
If you give me a $5 bill for something that costs $3.80, I might hand you a dime and say "3.90", then hand you another dime and say "4 dollars", and then hand you a dollar bill and say "And one dollar makes five" or something like that.
That's how I was trained to return cash change at In-N-Out, though our assumption was coin change was de facto correct:
"$3.80. $4. $5. $10. $15. $20." (Tens were mythic items. We never had them...)
opusthepenguin wrote:I used your method as well. I can state pretty confidently that I wouldn't have gotten that done in time to ring in. I think most contestants wouldn't. You sort of have to look at the equation, deduce that it's quickly solvable, ring in, and hope that your brain gears don't lock up in fright when Alex calls your name. (But if they do, you should shout "Bourbon!")
opusthepenguin wrote:I used your method as well. I can state pretty confidently that I wouldn't have gotten that done in time to ring in. I think most contestants wouldn't. You sort of have to look at the equation, deduce that it's quickly solvable, ring in, and hope that your brain gears don't lock up in fright when Alex calls your name. (But if they do, you should shout "Bourbon!")
opusthepenguin wrote:I used your method as well. I can state pretty confidently that I wouldn't have gotten that done in time to ring in. I think most contestants wouldn't. You sort of have to look at the equation, deduce that it's quickly solvable, ring in, and hope that your brain gears don't lock up in fright when Alex calls your name. (But if they do, you should shout "Bourbon!")
opusthepenguin wrote:I used your method as well. I can state pretty confidently that I wouldn't have gotten that done in time to ring in. I think most contestants wouldn't. You sort of have to look at the equation, deduce that it's quickly solvable, ring in, and hope that your brain gears don't lock up in fright when Alex calls your name. (But if they do, you should shout "Bourbon!")
