Start from zero — the basic math you need before everything else
What is 2 + 3 × 4? If you add first you get 20. If you multiply first you get 14. Both can't be right, so everyone follows one fixed order of operations. That way everyone gets the same answer.
The order is: Brackets first, then powers (exponents), then Multiply and Divide, and finally Add and Subtract. One common name is PEMDAS. When two operations are at the same level (like × and ÷, or + and −), just work left to right.
Order matters in real life: socks before shoes, not the other way round. Maths fixes one order so a sum has a single answer. Say you read 2 pages, then 3 chapters of 4 pages each — you must work out the 3 chapters (3 × 4) before adding the 2, or the page count comes out wrong.
▶ Order of Operations