8 Year Old's Maths Question

[Deleted member 26715]

View attachment 522249

Not seen that not sure he's taught that way

 

[Electric_Andy]

Not seen that not sure he's taught that way

yeah he's taught that way, he remembered how to write the table out from school. but needed reminding what you multiple first and then what to add up

 

[Levo-Lon]

It’s not a trick question, they are teaching children how a long number is made up.
1000
800
40
6

Or how to be an Auctioneer

 

[MontyVeda]

Oi it's Math. Don't put an 'S' on it with a Math Teacher around. I still call it MathS at work - drives the MathS team mad.

Nope math is for USA folk, always been maths in UK.

My American cousin, a college professor, never stepped foot outside of the USA, believes that maths is a more logical abbreviation than math.

 

[srw]

View attachment 522249

That's just a long-winded way of writing out a standard multiplication, which falls over as soon as you need to multiply by something with more than a single digit.

 

[matticus]

That's just a long-winded way of writing out a standard multiplication, which falls over as soon as you need to multiply by something with more than a single digit.

Yes, that was my reaction. But I think the advantage (of sorts) is that it slows the process down, and makes it more clear that one column is the 1,000s, one for 100s, etc; when we do it the normal (faster) way, we kinda hide from ourselves the mechanism that makes it work.

Kids COULD learn to do the fast way without actually understanding why it works. Which in the long-run will make them worse at doing sums. <but what do I know ... I've only taught physics, never Math! >

 

[MartinQ]

There are quite a few "different" ways to multiply.
https://en.m.wikipedia.org/wiki/Multiplication_algorithm

A couple of "tricks" which can be used in some circumstances

Use a difference of two squares to rewrite the problem so
45^2 = 40*50 + 5^2 = 2,025
And in the same way
106^2 = 100*112 + 6^2 = 11,236

Or use "convoultion" when the digits are fairly smalll. This flips one of the numbers then slides it under the other and you calculate each digit of the answer in turn. So something like
123*12
Flio the 12 to become 21,and slide it under the other number from the right and each time add up the product of digits. So the ones in the answer is
3*2 = 6
The tens is
2*2 + 3*1 = 7
hundreds is
1*2 + 2*1 = 4
Thousands is
1*1 = 1
So 1476. Each step, you're working directly on one of the digits in the answer, so you can just write the answer down.

Health warning: don't try these tricks at dinner parties, unless you're trying to get everyone to leave.

 

[Archie_tect]

There are quite a few "different" ways to multiply.
https://en.m.wikipedia.org/wiki/Multiplication_algorithm

A couple of "tricks" which can be used in some circumstances

Use a difference of two squares to rewrite the problem so
45^2 = 40*50 + 5^2 = 2,025
And in the same way
106^2 = 100*112 + 6^2 = 11,236

Or use "convoultion" when the digits are fairly smalll. This flips one of the numbers then slides it under the other and you calculate each digit of the answer in turn. So something like
123*12
Flio the 12 to become 21,and slide it under the other number from the right and each time add up the product of digits. So the ones in the answer is
3*2 = 6
The tens is
2*2 + 3*1 = 7
hundreds is
1*2 + 2*1 = 4
Thousands is
1*1 = 1
So 1476. Each step, you're working directly on one of the digits in the answer, so you can just write the answer down.

Health warning: don't try these tricks at dinner parties, unless you're trying to get everyone to leave.

We were just taught long multiplication [and division] in the 60s which is really quick once you've learnt your times tables!

 

[Deleted member 26715]

We were just taught long multiplication [and division] in the 60s which is really quick once you've learnt your times tables!

That to me is the key, for some unknown reason somebody within the education system decided that teaching times tables were not required, early 90's I think, neither of my 2 kids now in their 30's were taught times tables, I have no concept of how multiply numbers.

 

[Archie_tect]

We drilled times tables into our two. It's such an instinctive thing that even now we can slip "8 sevens are", or "six fours are", into conversations on Skype and they answer without thinking!

 

[swee'pea99]

That to me is the key, for some unknown reason somebody within the education system decided that teaching times tables were not required, early 90's I think, neither of my 2 kids now in their 30's were taught times tables, I have no concept of how multiply numbers.

Presumably it fell foul of a general hostility to rote learning - as so often, a sound basic idea taken to unhelpful extremes by well-meaning halfwits.

 

[Archie_tect]

I think of it as education policymakers deliberately changing things for the sake of it to stay viably employed. That's why we suffered the trauma of changing from 2 stage [5/11/18] to 3 stage [5/9/13/18] and now parents have had to endure similar upheaval back to 2 stage [5/11/18] all within 25 years... just long enough for each policy innovation to appear a 'good idea'.

 

[C R]

The countable vs uncountable infinities thing was one of my "wow" moments.

The other was when e^i pi + 1 = 0 dropped out of a result we were shown on the blackboard. I think we all gasped out loud when we first saw that

That has to be the most beautiful equation in history, so much mathematics in such an elegant expression.

 

[Deleted member 26715]

I think of it as education policymakers deliberately changing things for the sake of it to stay viably employed.

10/10

 

[Ming the Merciless]

We drilled times tables into our two. It's such an instinctive thing that even now we can slip "8 sevens are", or "six fours are", into conversations on Skype and they answer without thinking!

Six fours is 444,444