NCERT Solutions
Class 7 Maths
Algebraic Expressions

Ex.12.4 Q.2
Use the given algebraic expression to complete the table of number patterns:
(i) 2n - 1
Putting n = 100, 2 * 100 – 1 = 200 – 1 = 199
(ii) 3n + 2
Putting n = 5, 3 * 5 + 2 = 15 + 2 = 17
Putting n = 10, 3 * 10 + 2 = 30 + 2 = 32
Putting n = 100, 3 * 100 + 2 = 300 + 2 = 302
(iii) 4n + 1
Putting n = 5, 4 * 5 + 1 = 20 + 1 = 21
Putting n = 10, 4 * 10 + 1 = 40 + 1 = 41
Putting n = 100, 4 * 100 + 1 = 400 + 1 = 401
(iv) 7n + 20
Putting n = 5, 7 * 5 + 20 = 25 + 20 = 55
Putting n = 10, 7 * 10 + 20 = 70 + 20 = 90
Putting n = 100, 7 * 100 + 20 = 700 + 20 = 720
(v) n2 + 1
Putting n = 5, 5 * 5 + 1 = 25 + 1 = 26
Putting n = 10, 10 * 10 + 1 = 100 + 1 = 101
Putting n = 100, 100 * 100 + 1 = 10000 + 1 = 10001