Number Operations and Properties

15 million = 15,000,000 = 1.5 × 10,000,000 = 1.5 × 10^7. The decimal moves 7 places left to put one digit before it.

2's complement of a number is obtained by adding 1 to the 1's complement of that number.

The answer of 11 x 2 x 22 will be 484, which is same as the answer of 22 x 11 x 2. So, if we change the place of the numbers to be multiplied, answer will remain same.

This is the right answer. If we multiply 6 by 5 we will get 30. And to make the equation correct we should multiply 3 by the number which will give answer 30, and that number will be 10.      6 x 5 = 10 x 3          i.e. 30 = 30

This is the right answer. Multiplication is repeated addition. Here 8 is getting added 6 times, so to make it simple if we multiply 6 from 8 we will get the same answer.

This is the right answer. As if we multiply 100 by 1000 we will get 100000.

Let the successive numbers be n and n + 1. Given: n * (n + 1) = 4556 n² + n = 4556 n² + n - 4556 = 0 On solving this, we will get 67 and 68. So, the larger number is 68.

Let x be the number to be multiplied then, (-7/4) (x) = 3/8 Or, x = -3/14

8 and 14 are even numbers.

The expression {(30 + 45) / 5} + {(18 - 3) x 20} can be solved by simplifying the brackets. {(30 + 45) / 5} + {(18 - 3) x 20} = {75 / 5} + {15 x 20} = 15 + 300 = 315  Hence, the value of the given expression is 315. The correct answer is option (1). 

Since 20 > 6, the difference of 20 and 6 can be represented as (20 - 6). Accordingly, the multiplication of 39 with the difference of 20 and 6 can be represented as 39 x (20 - 6). Thus, the required expression is 39 x (20 - 6). The correct answer is option (4). 

Multiply 56 by 32: 56 × 32 = 56 × 30 + 56 × 2 = 1680 + 112 = 1792. Answer D is correct.

231 - 87 = 144

26 - 14 = 12     

45 - 23 = 22