NCERT Class 7 Mathematics

SIMPLE EQUATIONS 79 4.4 WHAT EQUATION IS? In an equation there is always an equalitysign. The equality sign shows that the value ...

80 MATHEMATICS (iii) One fourth of m is m 4. It is greater than 7 by 3. This means the difference ( m 4 7
) is 3. The equation ...

SIMPLE EQUATIONS 81 EXERCISE 4.1 Complete the last column of the table. S. Equation Value Say, whether the equation No. is sat ...

82 MATHEMATICS Set up an equation in the following cases: (i) Irfan says that he has 7 marbles more than five times the marbles ...

SIMPLE EQUATIONS 83 If we take any other numerical equation, we shall find the same conclusions. Suppose, we do not observe thes ...

84 MATHEMATICS To confirm whether we are right, we shall put x= 5 in the original equation. We get L.H.S. = x+ 3 = 5 + 3 = 8, wh ...

SIMPLE EQUATIONS 85 Now divide both sides by 3, 3 3 n = 18 3 (Step 2) or n = 6, which is the solution. (b) What should we do her ...

86 MATHEMATICS EXERCISE 4.2 Give first the step you will use to separate the variable and then solve the equation: (a)x – 1 = 0 ...

SIMPLE EQUATIONS 87 As we have seen, while solving equations one commonly used operation is adding or subtracting the same numbe ...

88 MATHEMATICS Check L.H.S. =




2 11 2 3211 2 6 2 2 11 6 2            = –2
5 2 25 2  5      = R.H.S. ...

SIMPLE EQUATIONS 89 EXERCISE 4.3 Solve the following equations. (a)^2 5 2 37 2 y (b) 5t + 28 = 10 (c) a 5  (^32) (d) q 4  ...

90 MATHEMATICS The required number is 7. (We may check it by taking 3 times 7 and adding 11 to it. It gives 32 as required.) EXA ...

SIMPLE EQUATIONS 91 EXERCISE 4.4 Set up equations and solve them to find the unknown numbers in the following cases: (a) Add 4 ...

92 MATHEMATICS Solve the following riddle: I am a number, Tell my identity! Take me seven times over And add a fifty! To reach ...

5.1 INTRODUCTION You already know how to identify different lines, line segments and angles in a given shape. Can you identify t ...

94 MATHEMATICS Again recall that an angle is formed when lines or line segments meet. In Fig 5.1, observe the corners. These cor ...

LINES AND ANGLES 95 THINK, DISCUSS AND WRITE Can two acute angles be complement to each other? Can two obtuse angles be complem ...

96 MATHEMATICS Fig 5.6 Do you notice that the sum of the measures of the angles in each of the above pairs (Fig 5.6) comes out t ...

LINES AND ANGLES 97 What will be the measure of the supplement of each one of the following angles? (i) 100º (ii) 9 0 º (iii) 5 ...

98 MATHEMATICS Fig 5.9 In the given Fig 5.10, are the following adjacent angles? (a) ∠AOB and ∠BOC (b) ∠BOD and ∠BOC Justify yo ...