Question

The sum of the successor and predecessor of $100$ is
A. 101
B. 199
C. 200
D. 111

Answer 1

Hint:We first explain the concept of successor and predecessor of any number. Then we explain the process to get a successor and predecessor of that number. We take the sum of those numbers and find the simplified form of the sum in its general form.

Complete step by step answer:
The successor and predecessor of a number can be found by adding and subtracting 1 respectively from that number. We add and subtract 1 from the number 100 to get the successor and predecessor of 100. The successor of 100 is $100+1=101$ and the predecessor of 100 is $100-1=99$. Now we find the sum of the successor and predecessor and get $99+101=200$.

Therefore, the sum of the successor and predecessor of 100 is 200.

Note:We can also find the simplified form of the sum of the successor and predecessor of any number in the form of variable $a$. We find the successor and predecessor of $a$.
The successor and predecessor of $a$ will be $a+1$ and $a-1$ respectively.
The sum will be $a+1+a-1=2a$.
Therefore, in general the sum of the successor and predecessor of any number is twice of that number itself. For 100, we got $2\times 100=200$.