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primary 5 | Maths | Whole Numbers
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Katie
Katie

primary 5 chevron_right Maths chevron_right Whole Numbers chevron_right Singapore

How to do this?

Date Posted: 4 years ago
Views: 328
Eric Nicholas K
Eric Nicholas K
4 years ago
The trick is to group them this way.

1 + 2 + 3 + ... + 98 + 99 + 100
= (1 + 100) + (2 + 99) + (3 + 98) + ... + (49 + 52) + (50 + 51)

There are a total of 50 brackets with values 101 each.

So total sum is 101 x 50 = 100 x 50 + 1 x 50 = 5000 + 50 = 5050.
Eric Nicholas K
Eric Nicholas K
4 years ago
There is a formula for this based on this method of grouping, but it’s probably too advanced for you as algebraic expressions are required.
Katie
Katie
4 years ago
THKS!

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Tay Si Hui
Tay Si Hui's answer
1 answers (Tutor Details)
1st
Using the formula , S=n(n+1) divide by 2 .N is the last value.
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C Meen
C Meen's answer
81 answers (A Helpful Person)
Hope this helps
Katie
Katie
4 years ago
Yeah it does help THKS for Ur ideas/suggestions!