In an objective examination of 120 questions, 4 marks are allotted for every correct answer and 1 mark is deducted for every wrong answer. After attempting all 120 questions a student got a total of 290 marks. Find the number of questions he attempted wrong.

Simplification is the process of replacing a mathematical expression with a simpler, equivalent one. Simplifying an expression involves writing it in its simplest form, without any more adding, subtracting, multiplying, or dividing. For example, the expression 4 + 6 + 5 can be simplified to 15.    Simplification can involve: Algebraic expressions, Boolean expressions, Fractions, Conjunction elimination.  Simplification can help to: Reduce a fraction by canceling it to the lowest common factor (LCM) for both the numerator and the denominator to its lowest term Reduce an algebraic... Show more

Simplification is the process of replacing a mathematical expression with a simpler, equivalent one. Simplifying an expression involves writing it in its simplest form, without any more adding, subtracting, multiplying, or dividing. For example, the expression 4 + 6 + 5 can be simplified to 15. 
 

Simplification can involve: Algebraic expressions, Boolean expressions, Fractions, Conjunction elimination. 

Simplification can help to:
Reduce a fraction by canceling it to the lowest common factor (LCM) for both the numerator and the denominator to its lowest term
Reduce an algebraic expression by grouping and combining similar terms
Make an algebraic equation easy to understand 

When simplifying an algebraic expression, you should follow the order of operations:
Parentheses
Exponents
Multiplication and division
Addition and subtraction 

Some important techniques of simplification include:
Digital sum
Number system
Reciprocals
HCF & LCM
Percentages
Square & Cube 

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