Calculator: Fill & Download for Free

Mom : Our laundry man charges Rs 5 for ironing one cloth, how much will he charge for 19 clothes? Calculate quickly and tell me. He will come now, I've to keep exact change ready.Me : If he charges Rs 5 for one cloth, how much will he charge for 19 clothes? Let me see, let me see... Umm...*closes eyes, pretends mental calculations*(As my mom is not really educated,she sometimes struggles with such calculations.In such times she really regrets not being educated and not be able to calculate quickly. But she is really smart.Hence, in not so important stuff, I pretend to be confused or dumb and let her help herself and learn to be independent)Me : *muttering * Rs 5, 19 clothes.... Where is my calculator...Mom : (not so confidently in small voice, talking to herself) If there were 20 clothes, it would be around 100 (calculates on fingers). If it's one cloth less,means Rs 5 less from Rs 100.Me : *still calculating* wait give me 2 minutes. Yes, found calculator…Mom: Will it not be Rupees 5 less from Rs 100?Me: *purposely taking some more time in calculator* Yes. Calculator says it's Rs 95.And the happiness that my mom feels is incredible. She feels so proud of herself for calculating correct answer.Mom: (proudly now) All our money spent on our children's schooling went down the drain. These kids can't even do such small calculations. What did they teach you at school? We are not even educated, but still can do these calculations without this stupid calculator. Learn from us. Be smart.Me : Yes mom, I almost gave the correct answer.Mom: Of course, after so much time and then using calculator. I calculated it without calculator. I don't know how you people manage business. I think I need to come and supervise that as well... (and self bragging continues)I feel so happy to see her happy and confident!!It's really worth acting dumb!!

Once my partner and I responded to a call of a shoplifter. It was a 16-year-old girl who had stolen a scientific calculator. We called her dad and he began crying for shame over the phone. He said that she has SATs the next day and despite him working very hard to support his family, he could not afford the calculator. She told us the same thing. The store manager said that corporate policy mandated him to press charges. With a heavy heart, we brought her in. Somehow that paperwork got so botched that the case never made it to court and was dismissed (oops!). Also, on our way out of the store, my partner and I purchased that calculator. We knew someone who needed it.

Reverse your percentage calculations.Without using a calculator, please tell me, how much is 8 % of 50?You’re probably thinking, hmm, I know for a fact that 10 % is 5. So 8 % must be a little less. Probably around 4–4.5 something. Definitely not an integer, because 50 and 8 are not divisible. Lets go with 4.333 because… because…It’s exactly 4.I didn’t use my calculator.Instead, I reversed the calculation. Because 8 % of 50 is the same as 50 % of 8. Which (for most people) is a much more simple calculation to make in your head.It holds true for all numbers. Go ahead, try a few.4 % of 75?80 % of 50?30 % of 25?In some cases it greatly simplifies the calculation or makes it easier to approximate the result.Edit 1: True, with some numbers you’re screwed either way. For example, 73.1 % of 634.5. There is a reason the calculator was invented :)Edit 2: Yes, it works with numbers greater than 100. For example, 5 % of 2000 is the same as 2000 % of 5 (20 x 5).Edit 3: Some suggest a similar “trick” (which is actually just the traditional textbook formula for calculating percent): Multiply the numbers and divide by 100. For example 6 % of 70. First, you multiply. 6 x 70 = 420. Then divide by 100, which equals 4.2. This of course also holds true the other way around (70 % of 6) as per my original trick. The point of my trick is that sometimes the reverse calculation is easier to perform on the spot - for some people that is. If you don’t have that problem, fine, but please stop telling me.Edit 4: Getting a little hate in the comments. Please, calm down math savvy Quorans. If your method of cracking percentages is so much better, faster and simpler than mine, feel free to keep using that method for as long as you’d like. And hey, while you’re at it, why not share it with everybody by adding it as an answer to the original question :)