IE is a very broad field and has a lot of full flesh careers under its umbrella. So, the question that whether you would need a good grip in math or not will vary from job to job. For example, the IE jobs that will best suit a person with a math major will include data engineer, linear programmer Lean Manufacturing, developer, resource allocator, and operations research. All of these jobs ask for a very good hand at math, cs, and statistics. They hardly have anything to do with typical engineering skills like that of mechanics, industrial works, and design office. But they still come under the umbrella of IE because this industry heavily relies upon heavy stats, stat modeling, and stats optimization. That is why it is advised for all the IE aspirants, to have a good understanding of concepts of statistics, organization, analysis, interpretation, and presentation of data to make a fruitful career.
At the undergraduate level, Industrial Engineers are made to study various types of basic and advanced math courses including calculus, statistics, numerical analysis, linear algebra, operations research, analytical solutions, numerical methods, etc. You might or might not use them in day-to-day activities when you pass out your high school and enter the industry, but they will surely help you to develop an analytical mindset that is very valuable for problem-solving abilities.
So even if you are not the most brilliant student in the class when it comes to grasping and mathematical concepts, IE still has a lot to offer you. It is just a matter of hard work, consistency, and basic problem-solving concepts that will lead you to a remarkable career in industrial engineering. I remember once in a younger grade, a kid asks, “Why do I need to know algebra? No one needs to know algebra.” And my Math teacher replied, “You won’t, but the smart kid will.” Industrial Engineers are those smart kids.