Ex 7.2, 2 - Chapter 7 Class 8 Cubes and Cube Roots

Transcript

Ex 7.2, 2 State true or false. (i) Cube of any odd number is even. False 3^3 = 27 7^3 = 343 Cube of odd number is always Odd. Ex 7.2, 2 State true or false. (ii) A perfect cube does not end with two zeros.True 〖10〗^3 = 1000 〖20〗^3 = 8000 〖1300〗^3 = 2197000000 A perfect cube doesn’t end with 2 zeroes. Ex 7.2, 2 State true or false. (iii) If square of a number ends with 5, then its cube ends with 25.False Since 〖15〗^2 = 275 〖15〗^3 = 3375 The given statement is false. Ex 7.2, 2 State true or false. (iv) There is no perfect cube which ends with 8.False 2^3 = 8 〖12〗^3 = 1728 So, there are perfect cubes like 8 & 1728 that end with 8. Ex 7.2, 2 State true or false. (v) The cube of a two digit number may be a three digit number.False Minimum two digits number = 10 & 〖10〗^3 = 1000 Minimum two digits number = 199 & 〖99〗^3 = 970299 So, cube of two digit number cannot be a 3 digit numbers. Ex 7.2, 2 State true or false. (vi) The cube of a two digit number may have seven or more digits.False Minimum two digits number = 10 & 〖10〗^3 = 1000 Minimum two digits number = 199 & 〖99〗^3 = 970299 So, cube of two digit number cannot have seven or more digits. Ex 7.2, 2 State true or false. (vii) The cube of a single digit number may be a single digit number.