Addition is one of the four basic operations of arithmetic, with the others being subtraction, multiplication and division. The addition of two whole numbers is...
Multiplication of whole numbers is equivalent to a repeated addition; that is, the multiplication of two numbers is equivalent to adding as many copies of one...
Shortcut 99: nCr=n!/[r!(n-r)!] Question: In how many ways 2 shirts and 3 pants can be selected from 5 shirts and 7 pants? Answer: Selecting...
Shortcut 95: Repeated elements n!/(a!*b!) Question: In how many ways the letters of the word “ENVIRONMENT” can be arranged? Answer: n = 11 Let,...
Shortcut 91: Events Dependent=multiplication Independent =addition Question: There 3 busses from city A to city B and there are 5 busses from city...
Shortcut 87: Using the odd days Question: Find the day of birth of MS Dhoni (7 July, 1981), if 31 Dec 1999 is Friday...
Shortcut 85: Using tanƟ Ɵ tan 0 0 30 [latex]1/\sqrt3 [/latex] 45 1 60 [latex] \sqrt3[/latex] 90 ...
Shortcut 82: Maximum number of items per group Take HCF Question: There are 40, 45 and 50 balls in three different colors. They have...
Shortcut 77: Divisibility test Divisibleby Rule 2 Last digit of a number should be 0,2,4,6, or 8 3 Sum of the digit should be divisible...
Shortcut 75: Simple interest [latex]SI=\frac{PNR}{100}[/latex] P = Principle amount invested or borrowed R = Rate of interest per term N = Number of terms Term...
