http://www . math . uwaterloo . ca/navigation/Current/transfer _ policy . shtml
It doesn't matter how well you score in the English exam (and in fact, I've heard many people say that IELTS is easier than TOEFL)
It mainly depends on your score. If you want to go to coop, you must meet coop's English requirements.
In addition, if you apply for a math department, it doesn't matter if you get a high score in the culture class, even if your English score is poor or you didn't take the English test at all. You can go to elas first, but you can't enter coop at first, you can only transfer later.