Question

Find the predecessor of following number
 -380
[a] -381
[b] -318
[c] -813
[d] -831

Answer 1

Hint: Predecessor of a number is a number which comes before that number. It is obtained from the original by subtracting one from it. Hence subtract 1 form -380 and get the answer.

Complete step-by-step answer:

Successor: When we list integers in increasing order successor of a number is a number which comes immediately after that number, e.g. The successor of 10 is 11. It is obtained from the original number by adding one to it.
Predecessor: When we list integers in increasing order predecessor of a number is a number which occurs immediately before that number, e.g. The predecessor of 10 is 9. It is obtained from the original number by subtracting one from it.

The number is -380
Hence the predecessor of -380 is -380 -1
Since both 380 and 1 are less than 0, when we subtract the numbers, their absolute values will be added, and the answer will be the negative of the sum of the absolute values.
Absolute value of -380 = 380
Absolute value of -1 = 1
Hence -380 -1 = -(380+1) = -381.
Hence the predecessor of -380 is -381.
Hence option [a] is correct.

Note: When we add two numbers one of which is positive, and other is negative, then the sign of the number which has greater absolute value is present in the answer and the absolute values of the numbers are subtracted, e.g., 15+7.
Since -15 has a larger absolute value, a negative sign will occur in the answer.
Now difference if absolute values = 15-7=8.
Hence -15 +7 = -8.
When we add two numbers having the same sign, then the answer is of the same sign of the numbers, and the absolute value of the numbers are added, e.g., 15-7 = -15+ (-7)
Now 15+7 =22
Hence -15 +(-7)= -22