(This trick only works if you have memorised or can quickly calculate the squares of numbers. When two numbers differ by 2, their product is always the square of the number in between these numbers minus 1.Let me explain this rule by taking examples
18*20 = 19^2 - 1 = 361 - 1 = 360
25*27 = 26^2 - 1 = 676 - 1 = 675
Example.
Understand the rule by 1 more example 49*51 = 50^2 - 1 = 2500 - 1 = 2499
Mathematics is KING of ARTS and
QUEEN of SCIENCE...
My_Teacher
Mathematics has 25%formulas, 25%proofs and apply 25%thinking and 25%efforts.
In real life situations proofs are nothing but already existed stories(we know the solutions from all experienced people).
formulas are nothing but goals. we have so many goals b