# Maths Formulas For Class 7

Mathematics is so important in our life. Because we use mathematical equation in our daily life activities. Every student should have a clear understanding about the concepts and they try to learn the application of maths formulas for a required problem to get solution. Many of the students learnt the math formulas properly, but they do not know how and where to apply the formulas.Before learning formulas, you should need to learn the symbols and its meaning. Use associated graphs and diagrams to remember the formulas for the given condition. Since this technique grasps the mathematics basics, it will be good for your future. Refer the class 7 maths formulas to solve complex problems. Some of the topics involved in class 7 Mathematics are as follows:

• Number System
• Integers
• Fractions
• Decimals
• Mensuration
• Algebra
• Ratio and Proportion

## Class 7 Maths Formulas

 Proportion Formula Rules: Addition: $\frac{a}{b}+\frac{c}{d}=\frac{ad+bc}{bd}$ Subtraction: $\frac{a}{b}-\frac{c}{d}=\frac{ad-bc}{bd}$ Multiplication:$\frac{a}{b}=\frac{c}{d}$, then a*d = b*c Division : $\frac{\frac{a}{b}}{\frac{c}{d}}=\frac{ad}{bc}$ Set properties: Commutative property: $A\cup B=B\cup A$ $A\cap B=B\cap A$ Associative property:$(A\cup B)\cup C=A\cup (B\cup C)$ $(A\cap B)\cap C=A\cap (B\cap C)$ Algebraic Expression Expansion: $(a+b)^{2}=a^{2}+2ab+b^{2}$ $(a-b)^{2}=a^{2}-2ab+b^{2}$ $a^{2}-b^{2}=(a+b)(a-b)$ $(x+a)(x+b)=x^{2}+x(a+b)+(ab)$ Consumer Math Formulas: Simple Interest, $S.I=\frac{PTR}{100}$, Where P=Principal, T= Time in years,R=Rate of interest per annum Rate,$R=\frac{100 \ast S.I}{P \ast T}$ Principal,$P=\frac{100 \ast S.I}{R \ast T}$ Time,$T=\frac{100 \ast S.I}{R \ast P}$ Discount = MP-SP Principal = Amount – Simple Interest If Rate of Discount is given, $Discount=\frac{Past\; Rate\; of\; Discount}{100}$ Time and Speed: $Speed=\frac{Distance\; travelled}{Time\; taken}$ $Number\; of\; Revolution=\frac{Distance\; travelled}{Circumference\; of\; the\; wheel}$ Area Formulas for 2D and 3D Figures: Circle=$pi r^{2}$ Sq units, where r is the radius Rectangle= $l \ast b$ Sq.units , where l = length and b is breadth Total Surface Area for Cube = $6a^{2}$ sq.units Total surface Area of cuboid =$2(lb+bh+hl)$ Sq.units Perimeter Formulas Square = 4s units, where s is side of square Rectangle= 2(l+b) units, where l is length and b is breadth Volume Formulas: Cube =$l^{3}$ cu.units Sphere=$\frac{4}{3}\pi r^{3}$ cu.units,where r is the radius of the sphere. Cylinder= $\pi r^{2}h$ cu.units,where r is the radius of the base,h is the height of the cylinder.

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#### Practise This Question

Which of the following is the side view of the given figure?