Maths book 1 paper 3 question 16

[gilbertstone]

How do you work out what is the nearest number to 1000 but smaller than 1000, into which 38 will divide with no remainder?

[Hera]

One way would be to divide 1000 by 38 which would give you 26 remainder 12 and take the 12 away from 1000.

[gilbertstone]

hi bel the answer is 988 but how do you work it out need explanation?

[Reading Mum]

standard long division I would have thought - my DD calls it the bus shelter method for some reason

[daveg]

standard long division I would have thought - my DD calls it the bus shelter method for some reason

Unlikely that long division is necessary: this is an excellent example of where "chunking" is a far faster method, and I suspect the question is set assuming that's how you'll do it, because it's particularly tidy. 1000/38 is "a bit more than 25" (assuming you recognise that 1000/40 is 25). 25 * 38 is 950 (divide 38 by 4 and multiply the result by 100). Once you know that 25 x 38 = 950, the rest is pretty straightforward. Dividing 1000/38 using standard long division is much harder (100/38 = 2 remainder 24, but it's not obvious, and 240/38 = 6 remainder 12 isn't obvious at all).

[Reading Mum]

Dd would probably chunk - I am way too old for that to come naturally to me

[yoyo123]

The 'bus stop ' method is short multiplication; took me ages to work out what they were talking about and I was the teacher!

[tiredmumof2]

I would do it simply (because I'm not good enough to do it in a complicated way) by timesing by 10 - so 20 x 380=760.

30 x is 1140 so too much. So add 5 x:

760 +190 =950 so you know has to be 26 times at 988.

[daveg]

I would do it simply (because I'm not good enough to do it in a complicated way) by timesing by 10 - so 20 x 380=760.

30 x is 1140 so too much. So add 5 x:

760 +190 =950 so you know has to be 26 times at 988.

That's chunking, as it happens.

[Bappa11]

I am new to this forum, and my DD will take her 11+ in 2015. I find this forum very useful with all the great tips. Trying to devise a plan to help her deal with the exam conditions and think logically. I'm surely going to use this forum a lot in the coming days.
Was curious about the question posted by OP, and am just giving my opinion. The dividend is what is required, not the quotient. So chunking is the ideal method.
I would teach my DD to use easy multiples of 38 and get close to 1000
38x10=380
double it
760
38x5=190
add 760 +190= 950
50 left
add 38 950+38= 988
Agree with tiredmumof2 there, not completely The answer is 988. The quotient is irrelevant in this particular context.