Does anyone do math in their head like I do ?
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Was having a discussion today with my sister and her kids (aged 17 and 13 so they're well up on school math techniques). Someone mentioned some woman who'd had 18 kids and my sister raised the question of how many years of her life the woman must have spent pregnant.
In my mind I went this way:
Well 9 months is 3/4 of a year, she's had 18 kids, so what's 3/4 of 18. As a quarter is a half of a half, I went a half of 18 is 9 and half of 9 is 4.5, so 3 times 4.5 is (12 plus 1.5) is 13.5. I'd say that took about 2 seconds to think of the answer.
The other three started thinking this way (after I'd already finished working it out in my head), they were saying OK what's 9 (months) times 18 (kids) ... err, ok it's 9x8 is 72 so that's 2 carry the 7 and then 9 times 1 etc etc. It was at this painful point I had to interrupt them and tell them there's a much easier way of working it out even if they do want to work it out in months. Instead of what's 9 times 18, work out the much easier 10 times 18 and then subtract one 18 (180-18=162). They all said they would never have dreamed of working it out that way. They then proceeded to figure out what 162 divided by 12 is to eventually get 13.5. I think it took them a good 30-40 seconds in the end.
It was so painful seeing how other people work out math in their head. Am I a freak ? Does everyone do it the hard way ? Please someone tell me they would have worked it out like I did.
In my mind I went this way:
Well 9 months is 3/4 of a year, she's had 18 kids, so what's 3/4 of 18. As a quarter is a half of a half, I went a half of 18 is 9 and half of 9 is 4.5, so 3 times 4.5 is (12 plus 1.5) is 13.5. I'd say that took about 2 seconds to think of the answer.
The other three started thinking this way (after I'd already finished working it out in my head), they were saying OK what's 9 (months) times 18 (kids) ... err, ok it's 9x8 is 72 so that's 2 carry the 7 and then 9 times 1 etc etc. It was at this painful point I had to interrupt them and tell them there's a much easier way of working it out even if they do want to work it out in months. Instead of what's 9 times 18, work out the much easier 10 times 18 and then subtract one 18 (180-18=162). They all said they would never have dreamed of working it out that way. They then proceeded to figure out what 162 divided by 12 is to eventually get 13.5. I think it took them a good 30-40 seconds in the end.
It was so painful seeing how other people work out math in their head. Am I a freak ? Does everyone do it the hard way ? Please someone tell me they would have worked it out like I did.
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I tend to do it your way...otherwise I would forget the question by the time I had the answer.
My dad used to add our groceries in his head as we were checking out, and would have a total before the cashier did. I was never that good at it though... being a girl and all I guess
My dad used to add our groceries in his head as we were checking out, and would have a total before the cashier did. I was never that good at it though... being a girl and all I guess
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Originally Posted by DD_545i' post='1000272' date='Sep 6 2009, 04:09 PM
Was having a discussion today with my sister and her kids (aged 17 and 13 so they're well up on school math techniques). Someone mentioned some woman who'd had 18 kids and my sister raised the question of how many years of her life the woman must have spent pregnant.
In my mind I went this way:
Well, 9 months is 3/4 of a year, she's had 18 kids, so what's 3/4 of 18. As a quarter is a half of a half, I went a half of 18 is 9 and half of 9 is 4.5, so 3 times 4.5 is (12 plus 1.5) is 13.5. I'd say that took about 2 seconds to think of the answer.
The other three started thinking this way (after I'd already finished working it out in my head), they were saying OK what's 9 (months) times 18 (kids) ... err, ok it's 9x8 is 72 so that's 2 carry the 7 and then 9 times 1 etc etc. It was at this painful point I had to interrupt them and tell them there's a much easier way of working it out even if they do want to work it out in months. Instead of what's 9 times 18, work out the much easier 10 times 18 and then subtract one 18 (180-18=162). They all said they would never have dreamed of working it out that way. They then proceeded to figure out what 162 divided by 12 is to eventually get 13.5. I think it took them a good 30-40 seconds in the end.
It was so painful seeing how other people work out math in their head. Am I a freak ? Does everyone do it the hard way ? Please someone tell me they would have worked it out like I did.
In my mind I went this way:
Well, 9 months is 3/4 of a year, she's had 18 kids, so what's 3/4 of 18. As a quarter is a half of a half, I went a half of 18 is 9 and half of 9 is 4.5, so 3 times 4.5 is (12 plus 1.5) is 13.5. I'd say that took about 2 seconds to think of the answer.
The other three started thinking this way (after I'd already finished working it out in my head), they were saying OK what's 9 (months) times 18 (kids) ... err, ok it's 9x8 is 72 so that's 2 carry the 7 and then 9 times 1 etc etc. It was at this painful point I had to interrupt them and tell them there's a much easier way of working it out even if they do want to work it out in months. Instead of what's 9 times 18, work out the much easier 10 times 18 and then subtract one 18 (180-18=162). They all said they would never have dreamed of working it out that way. They then proceeded to figure out what 162 divided by 12 is to eventually get 13.5. I think it took them a good 30-40 seconds in the end.
It was so painful seeing how other people work out math in their head. Am I a freak ? Does everyone do it the hard way ? Please someone tell me they would have worked it out like I did.
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Originally Posted by DD_545i' post='1000272' date='Sep 6 2009, 04:09 PM
Was having a discussion today with my sister and her kids (aged 17 and 13 so they're well up on school math techniques). Someone mentioned some woman who'd had 18 kids and my sister raised the question of how many years of her life the woman must have spent pregnant.
In my mind I went this way:
Well 9 months is 3/4 of a year, she's had 18 kids, so what's 3/4 of 18. As a quarter is a half of a half, I went a half of 18 is 9 and half of 9 is 4.5, so 3 times 4.5 is (12 plus 1.5) is 13.5. I'd say that took about 2 seconds to think of the answer.
The other three started thinking this way (after I'd already finished working it out in my head), they were saying OK what's 9 (months) times 18 (kids) ... err, ok it's 9x8 is 72 so that's 2 carry the 7 and then 9 times 1 etc etc. It was at this painful point I had to interrupt them and tell them there's a much easier way of working it out even if they do want to work it out in months. Instead of what's 9 times 18, work out the much easier 10 times 18 and then subtract one 18 (180-18=162). They all said they would never have dreamed of working it out that way. They then proceeded to figure out what 162 divided by 12 is to eventually get 13.5. I think it took them a good 30-40 seconds in the end.
It was so painful seeing how other people work out math in their head. Am I a freak ? Does everyone do it the hard way ? Please someone tell me they would have worked it out like I did.
In my mind I went this way:
Well 9 months is 3/4 of a year, she's had 18 kids, so what's 3/4 of 18. As a quarter is a half of a half, I went a half of 18 is 9 and half of 9 is 4.5, so 3 times 4.5 is (12 plus 1.5) is 13.5. I'd say that took about 2 seconds to think of the answer.
The other three started thinking this way (after I'd already finished working it out in my head), they were saying OK what's 9 (months) times 18 (kids) ... err, ok it's 9x8 is 72 so that's 2 carry the 7 and then 9 times 1 etc etc. It was at this painful point I had to interrupt them and tell them there's a much easier way of working it out even if they do want to work it out in months. Instead of what's 9 times 18, work out the much easier 10 times 18 and then subtract one 18 (180-18=162). They all said they would never have dreamed of working it out that way. They then proceeded to figure out what 162 divided by 12 is to eventually get 13.5. I think it took them a good 30-40 seconds in the end.
It was so painful seeing how other people work out math in their head. Am I a freak ? Does everyone do it the hard way ? Please someone tell me they would have worked it out like I did.
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From: Europe
Originally Posted by augustrush42' post='1000303' date='Sep 6 2009, 10:55 PM
im actually pretty good with math and can work stuff out quick.. You couldve cut that down to 1.5 seconds by just saying half of 18 is 9 plus half of nine (4.5), 9 + 4.5 = 13.5
OK, so it's not just me then, it's my sister and her kids. I'll have to find a nearby walmart and send them there to get a cheap calculator each
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I learned it the same way you do it in school.
Oh, and BTW, you can't answer this question correctly, since you don't have all facts...
Maybe she has twins, etc....
Then it would be less...
Oh, and BTW, you can't answer this question correctly, since you don't have all facts...
Maybe she has twins, etc....
Then it would be less...
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From: Europe
Originally Posted by Iceman' post='1000337' date='Sep 6 2009, 11:54 PM
I learned it the same way you do it in school.
Oh, and BTW, you can't answer this question correctly, since you don't have all facts...
Maybe she has twins, etc....
Then it would be less...
Oh, and BTW, you can't answer this question correctly, since you don't have all facts...
Maybe she has twins, etc....
Then it would be less...
Interesting that you learned it that way in school ... I didn't.
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From: Europe
Originally Posted by Rudy' post='1000351' date='Sep 7 2009, 12:12 AM
I'm an excellent driver, dad let's me drive slow in the driveway...slow in the driveway.
Definitely ten minutes to Wapner... 
Definitely ten minutes to Wapner...
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I do math in my head with shortcuts including the *9 = *10 -1 and many other shortcuts.
Math was so easy I always got bored in the class. Teachers would have to find me extra work.
Math was so easy I always got bored in the class. Teachers would have to find me extra work.
