One of my professors, at uni, put it best. You should be able to second guess your calculator.
Also, it’s often faster to do an approximate calculation in your head, rather than getting out a calculator (or phone) and plugging the numbers in.
112 x 9.
By approximation, it’s 100ish by 10ish, so around 1000. This can often be enough. (E.g is a current below 1500mA?)
The calculator should give 1008. If it claims it is 10,080, or 12.4, you know you’ve screwed up, and should recheck your calculations. If you can’t do it in your head, then you can’t check for issues.
the thing is: the calculator will always get it right.
our brains use all kinds of shortcuts and patterns so it’s not even that rare for mental calculations to end up completely wrong, or you get the right answer but write the wrong thing, which is less likely to happen if you see the digits in front of you and copy them.
One of my professors, at uni, put it best. You should be able to second guess your calculator.
Also, it’s often faster to do an approximate calculation in your head, rather than getting out a calculator (or phone) and plugging the numbers in.
112 x 9.
By approximation, it’s 100ish by 10ish, so around 1000. This can often be enough. (E.g is a current below 1500mA?)
The calculator should give 1008. If it claims it is 10,080, or 12.4, you know you’ve screwed up, and should recheck your calculations. If you can’t do it in your head, then you can’t check for issues.
I do it in my head and then on a calculator because I don’t trust my head to do it correctly
Me: 4 + 4 = 8
Calculator: 4 + 4 = 150
Me: pft, stupid brain. This is why we have to use a calculator!
I had a coworker go get a calculator to put in, I shit you not, 10+190
I have to do this before my coffee in the morning. My tired brain can’t be trusted to do math.
the thing is: the calculator will always get it right.
our brains use all kinds of shortcuts and patterns so it’s not even that rare for mental calculations to end up completely wrong, or you get the right answer but write the wrong thing, which is less likely to happen if you see the digits in front of you and copy them.