4 ms·
Why are 7 and 8 the hardest to memorize?
by cactusface 11y ago
Why are 7 and 8 the hardest to memorize?
- callmeed 11y agoI don't know why, but as a parent of 4 I definitely think it holds true.
- iherbig 11y agoNo discernible pattern and the numbers very quickly get large, I imagine. 2 is always even. 3 only gets to 30 after 3 x 10. 4 has a quick pattern (4>8>2>6>0>..). 5 always ends in a 5 or a 0. 7's pattern is long 7>4>1>8>5>2>9>6>3>0>.. with no sense to it and the numbers get big fast. 8's pattern is short (8>6>4>2>0>..) but the numbers are unwieldy getting into the 40s really quickly. 9's pattern is easy: start with 09. Add one to tens-place and subtract one from ones-place. So it's long, but pretty: 9>8>7>6>5>4>3>2>1>0>.. I skipped 6 because it seems to me that 6 would probably be pretty difficult for the same reason 8 is difficult. Its pattern is short (6>2>8>4>0>..) but there's less sense to it than there is to 8's pattern, and the numbers get large rather quickly. At least, that's the reasoning I've always figured. I have no idea.
- cactusface 11y agoSeems reasonable to me. I'd say 7 is harder than 8. I think 6 is easy because it's 2 x 3 so you're already kind of familiar with the products.
- keithpeter 11y agoJust one idea: you don't come across things in multiples of 7 that often. UK: eggs come in 6s. Pizzas get cut into 4s and perhaps 8s for a really huge one, so multiples of those numbers get seen around. Half is sort of easy (all my adult students can usually find half of a figure, especially if I encourage them to think of paying it out in money with £10 notes and £1 coins). 5 fits into the decimal system nicely. Threes are easy to count up.
- beejiu 11y ago> Just one idea: you don't come across things in multiples of 7 that often. Days of the week?
- keithpeter 11y agoYou got me there! But just thinking around weeks, apart from a fortnight do you actually count the days in multiples of 7 or just think about months or a period of weeks?
- songshu 11y agoI became good at sevens working in a pharmacy store room in a large hospital where we did continue to count in weeks. Boxes of 112 were common. Inside you would find blister packs arranged in rows of seven with the days of the week printed.
- keithpeter 11y agoNice example!
- deleted 11y ago[deleted]
- Splendor 11y ago> Just one idea: you don't come across things in multiples of 7 that often. American football scores.
- keithpeter 11y agoI'm in the UK. I'll read up on those - US children should be better at their times tables than others then! http://www.theguardian.com/news/datablog/2013/may/31/times-tables-hardest-easiest-children http://www.theguardian.com/news/datablog/2013/may/31/times-t...
- GurnB 11y ago
- kendallpark 11y agoSome additions: 3's multiples' digits always add up to a multiple of three. So 69 is 6+9 which is 18, a multiple of three. 9's multiples' digits always add up to a multiple of nine. So 108 is 1+0+8 which is 9, a multiple of 9. 6's multiples' digits are always even and add up to a multiple of three.
- astrobe_ 11y ago2 * n is easy. 3 * n is easy, just multiply by 2 and add one n. 4 is easy, just multiply by 2, two times (or multiply by 5 and subtract one n). 5 is easy. Six is easy, just multiply by 5 and add one n. 9 is easy, just multiply by 10 and subtract one n. But 7 and 8 are not 'reachable' with two operations.
- astrobe_ 11y agoActually, Using those tips and commutativity, the only thing you need to know about 7 and 8 is 7 * 8.