You know with the advent of tools to help perform calculations for us one can get a bit lazy in the area of mathematics. A noticeable occurrence of this was today when I figured out how easy it was to convert C to F. Up until now I had been turning to Google to answer this question for me (I know, I know *smack's own wrist*). The equation is: F = ( C * 1.8 ) + 32 Thats... it.... Not quite difficult at all. So I was wondering have you any favourite calculations that you perform over and over again in your head and save you lots of time?
Having been brought up without calculators or computers I've always used my head to work out percentages, fractions etc. We were taught mental arithmetic at school and I still find it easier than using pen and paper or other devices. If I use a calculator I tend to work it out in my head too to make sure the machine is correct!!
In deciding where I am in time during Daylight Saving Time, I use the "formula" - Fall back, Spring forward in setting my clocks. Gardengater
I tend to stick with the easy formulas...figuring out how much to tip at a restaurant, how much something will cost when the price is marked down by a percentage or what the sales tax is going to be on a purchase.
I use Excel religiously... I think in Excel. =if(COFFEE<="2.99","yum","tea") If coffee is less than or equal to $2.99, drink up. Otherwise, just buy some tea...
I usually calculate the C and F degrees a little differntly but it comes out the same. 0 C = 32 F or freezing. 5 C = 40 F. 10 C = 50 F. so on and so on. i use incrimates of 5 or rounding off. For me its easier. I do the same with the American dollar and the Norwegian Crown. I just round up and its all even and no problem calculating when i need to convert.
I rely on the "I" alot...I guess that means I'm lazy. Awhile back, I posted this link for unit conversions and I think it's great, especially on a forum as this with so many from all around the globe: http://www.onlineconversion.com/
When my son was in college, he worked part time in a grocery as a cashier. They had the older type of register that the item and prices had to be entered by hand. No scanners. But when you hit total it would add it up. He used to keep a running total in his head and would compare it with the registers total. He would beat the register 9 out of 10 times, and once he even caught the register making a mistake. He is great with math, but can't balance his check book!
