# Edexcel C1 Examiners Report: 25 x 102

Discussion in 'Mathematics' started by Lee Fields, Aug 25, 2011.

1. ### Lee FieldsNew commenter

In the June 2011 C1 paper Question 9 (a) was:
Calculate the sum of all the even numbers from 2 to 100 inclusive,

2 + 4 + 6 + ...... + 100
The Examiners' Report commented :
"... Calculating 25 x 102 correctly, caused
problems for many."

So without a calculator, many A level students cannot work out 25 x 102 !
The Educational Commissars were asleep here, putting that appalling fact in the public domain!

2. ### KarvolOccasional commenter

Depends how you interpret the statement. I would have interpreted it as not many students were able to figure out that the sum is "25 x 102".
I don't teach A levels, so I could be wrong. ( I certainly hope not though! Far too scary a thought. )

3. ### Maths_MikeNew commenter

Afraid I would definitly think this means the calculation was the problem.
the formula 0.5n(a+l) is simple enough

4. ### stevencarrwork

Please sir! I know! 25 x 102 is 2550
I can well imagine some of my students having problems with that.

5. ### MathsHOD

Nah you've got it wrong .... everyone knows (well some of my year 11 know) that the way to do it is:

2 x 102 = 204
5 x 102 = 610

610 + 204 = 814