A couple of commas would help: 'The hundredth element, which is in the 5th group, is higher up the number line than the sum of the number of elements in smaller groups'. Also, 'the sum of the number of' is ambiguous; normally 'the sum of' = 'the number of'.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.