Hello fellow maths people, I studied a lot of maths at uni but I'm recently into doing some mental maths. I'm wondering, does anyone have any good mental techniques for doing 3 digit subtraction? For example: Whats: 452 - 376 = 761 - 628 = 432 - 259 = You should be able to answer each one within 4 seconds to be considered good. So does anyone have some good methods in their head for this? I can rarely work that fast in my head. Of course if its 430-225 its a lot easier but it's not always that simple.