Hi, can anyone help with question b please? Thank you.

Source: Nan Chiau Primary

Hi, can anyone help with question b please? Thank you.

Source: Nan Chiau Primary

alfretztay

I would solve (b) as follows ;

10 + 20 + 30 + … + 790 = (800 x 39) + 400 = **31600**

or

10 + 20 + 30 + … + 790 = (790 x 39) + 790 = **31600**

Ans : * 316m*.

Acestarling

You can use any method to find the sum of consecutive numbers from 10cm to 790cm ( in steps of 10 )

ski

Thank you Acestarling. I wasn’t sure initially if they could use algebra formula to calculate at P5.

Acestarling

Yes……Algebra is only covered in the early part of P6 level, hence may not be so “appropriate” for P5 question. However, there is not really any algebra involved here in the solution. The N(N+1)/2 is actually a standard “formula” for calculating the sum of consecutive numbers, you may use other alternative method which you are more familiar with.

Acestarling