My grandfather once bought 9 items of 90 cents each. So he put 8.10 on the counter. The cashier did the math on her cash register (this was before barcodes were introduced) and asked “Sir, how did you know it would be 8.10?”.
DavidHG — Cute trick…but most of those cute tricks are too confusing for the average person to remember.
A real grasp of numbers works better.
How can you multiply any number by 11 so it makes sense?
11 of anything is ten of them plus another one.
Ergo…11 times 57 is TEN 57’s plus another 57…
570 plus another 57….
And how do you add that in your head?
Several different ways…. easiest to teach has been 570 needs another 30 to make 600… take it from the 57….Now you have 600 and you still have 27 left over from your 57…627.
By the same token NINE 57’s Is 570 MINUS 57.
Might sound complicated but once I get people started with real objects…meaning I’d have them doing that with nickels and quarters and cookies and such before abstract numbers…it starts to ….um… add up.
This is a mental trick that’s always worked for me; Multiply everything by 10, move the decimal to wherever, add the difference in points over or under ten multiplied by their factors and add up (or subtract) the difference. Do it all in your head, write up the sum on your palm and when you get to the cashier, fight it out with HER scanner price total. Fun afternoon. Math gymnastics.. If I had to remember all the stunts that people ‘suggested’ I’d never have become the oh, look….. a bee !!
Well Agnes…Seems that teachers are always asking you questions they would like to know the answers for. Why not just give the teacher YOUR questions first thing in the morning?
It occurs to me our weary teacher may not have sent our beloved Agnes to our long-suffering principal..Agnes may have gone to express her complaint about the newfangled modification of RPS? We all get set in our ways every now and then — some worse than others..By the way, I used to have a problem remembering six times seven is forty-two. I just remembered it was six more than six times six, which I could remember was thirty-six or seven less than seven times seven, which I could always remember is forty-nine. I always calculated it both ways to check myself. .Years back we used pencil and paper to check our slide rule results, then used our slide rules to check our calculator results.
. Nowadays I use mental gyrations to check the store clerk totals. Most of them have no idea if the totals are reasonable, bless their well-meaning hearts. .They don’t yet know they may have entered it wrongly, scanned it thrice, the prices may have been stored incorrectly or the computer may have been misprogrammed for sales taxes.
Harry Grapjas about 11 years ago
My grandfather once bought 9 items of 90 cents each. So he put 8.10 on the counter. The cashier did the math on her cash register (this was before barcodes were introduced) and asked “Sir, how did you know it would be 8.10?”.
SusanSunshine Premium Member about 11 years ago
DavidHG — Cute trick…but most of those cute tricks are too confusing for the average person to remember.
A real grasp of numbers works better.
How can you multiply any number by 11 so it makes sense?
11 of anything is ten of them plus another one.
Ergo…11 times 57 is TEN 57’s plus another 57…
570 plus another 57….
And how do you add that in your head?
Several different ways…. easiest to teach has been 570 needs another 30 to make 600… take it from the 57….Now you have 600 and you still have 27 left over from your 57…627.
By the same token NINE 57’s Is 570 MINUS 57.
Might sound complicated but once I get people started with real objects…meaning I’d have them doing that with nickels and quarters and cookies and such before abstract numbers…it starts to ….um… add up.
J Short about 11 years ago
It’’s too early for this, my head hurts.
Comic Minister Premium Member about 11 years ago
Nice to see her teacher again! But this time she must have dyed her hair blonde.
Stephen Gilberg about 11 years ago
I forgot we’d ever seen her before. Looks kinda like a younger version of Grandma.
unca jim about 11 years ago
This is a mental trick that’s always worked for me; Multiply everything by 10, move the decimal to wherever, add the difference in points over or under ten multiplied by their factors and add up (or subtract) the difference. Do it all in your head, write up the sum on your palm and when you get to the cashier, fight it out with HER scanner price total. Fun afternoon. Math gymnastics.. If I had to remember all the stunts that people ‘suggested’ I’d never have become the oh, look….. a bee !!
rshive about 11 years ago
Well Agnes…Seems that teachers are always asking you questions they would like to know the answers for. Why not just give the teacher YOUR questions first thing in the morning?
David Huie Green LosersBlameOthers&It'sYOURfault about 11 years ago
It occurs to me our weary teacher may not have sent our beloved Agnes to our long-suffering principal..Agnes may have gone to express her complaint about the newfangled modification of RPS? We all get set in our ways every now and then — some worse than others..By the way, I used to have a problem remembering six times seven is forty-two. I just remembered it was six more than six times six, which I could remember was thirty-six or seven less than seven times seven, which I could always remember is forty-nine. I always calculated it both ways to check myself. .Years back we used pencil and paper to check our slide rule results, then used our slide rules to check our calculator results.
. Nowadays I use mental gyrations to check the store clerk totals. Most of them have no idea if the totals are reasonable, bless their well-meaning hearts. .They don’t yet know they may have entered it wrongly, scanned it thrice, the prices may have been stored incorrectly or the computer may have been misprogrammed for sales taxes.
jack fairbanks about 11 years ago
traditional parent trump. remember you’ll pick their nursing home