Complex sentence: Out of that number, 140 are elected in ten multi-seat constituencies, defined on the basis of existing county borders, with necessary amendments to achieve a uniform number of eligible voters in each constituency (within five percent).
Split into simpler sentences: Out of that number, 140 are elected in ten multi-seat constituencies. Ten constituencies are defined on the basis of existing county borders, with necessary amendments to achieve a uniform number of eligible voters in each constituency (within five percent).