@Lateef10478, it's constant

@DrDayo, so what can we do if our child weighs more than 9kg at 9 months?

@DrDayo, but Dr, what If I have to calculate the expected weight of 2, 3 or 5 month old baby, will it be constant (n + 9) / 2 or ( n + 3) /2 for 3 months old.?