Question: Multiples

[fluffygirl_27]

Find the sum of the multiples of 5 from 5 to 200

Thanks

[Qeb2019]

Find the sum of the multiples of 5 from 5 to 200

Thanks

Multiple of 5 from 5:

5,10,15,....,195,200

There are 40 numbers or 20 pairs

If pair them 5+200,10+195....there are 20 pairs each pair is equal 205, therefore total is: 205x20=4100.

Hope that helps

[ToadMum]

Find the sum of the multiples of 5 from 5 to 200

Thanks

Is this another piece of homework set by your DC's tutor? When they get the answer right, are they going to say, 'I only know how to do this becsuse Mum asked on the internet and someone told her the answer', or will they let the tutor think that they actually worked it out for themselves? Were I a tutor, I would want to know if my tutee hadn't been able to get the answer, if they genuinely couldn't, but would want to know what unsuccessful process(es) they had gone through (not) to get there.

[solimum]

Apocryphally a French school teacher once asked a class of 11-year old boys to add up all the numbers from 1 to 100 (to keep them busy while he did something else..) . The young Pascal however spotted the trick (add 1 to 100, 2 to 99 .... = 100 x 101 then divide by 2) and came up the with answer 5050 in seconds. Most of us however will only know the trick once it's been pointed out, or calculate the general expression 1/2 n(n+1)