Grade 9 - Commercial Math

Commercial Mathematics

(i) Percentage
(a) Percentage; Percentage increase/decrease applications: increase/decrease in price, addition/subtraction of tax, effect of discount/mark-up, profit/loss.
(b) Simple problems related to basic/cost price, marked price, selling price including inverse working.
(ii) Simple Interest
(a) Direct problems based on the formula S.I. = PRT/100, i.e. given any three quantities of SI, P, R, T, to find the fourth.
(b) To find the “Amount” based on the above.

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Arithmetic
Irrational Numbers
Rational, irrational numbers as real numbers, their place in the number system. Surds and rationalization of surds.

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Algebra

Framing of Formulae Simple framing including change of subject and substitution.
(Linear Equations and Simultaneous (linear) Equations
Solving algebraically (by elimination as well as substitution) and graphically.

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Geometry
Angles formed at a point by two intersecting lines and parallel lines and a transversal Adjacent, supplementary, linear pair, vertically opposite, alternate, corresponding, allied (co-interior) and their properties.
Triangles

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Statistics
Tabulation of raw data using tally-marks.
Understanding and recognition of raw, arrayed and grouped data.

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Mensuration
Formulae for area and perimeter of simple 2-D figures: triangle (including Hero’s formula for area), square, rhombus, rectangle, parallelogram and trapezium. Simple direct problems based on these including those involving inner and outer dimensions, cost.

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Trigonometry
Trigonometric Ratios: sine, cosine, tangent of an angle and their reciprocals.
Trigonometric ratios of standard angles- 0, 30, 45, 60, 90 degrees.

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Co-ordinate Geometry
Dependent and independent variables.
Ordered pairs, co-ordinates of points and plotting them in the Cartesian Plane.

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