Number System Problems To Prepare For PO Exams

Dear Reader,
Below are four problems on basic arithmetic calculations of addition and subtraction.
Question 1
9857 - ? = 4343
a) 5014 b) 4914 c) 6714 d) 5514

Answer : d) 5514
Solution :
Let X be the value of ?.
Then, 9857 - X = 4343
-X = 4343 - 9857
X = 9857 - 4343 = 5514
Question 2
6523 + 785 + 963 - ? = 7003
a) 1268 b) 2098 c) 1668 d) 998
Answer : a) 1268
Solution :
Let X be the value of ?.
Then, 6523 + 785 + 963 - X = 7003
8271 - X = 7003
-X = 7003 - 8271
X = 8271 - 7003 = 1268.
Question 3
3437001 - ? = 1356218
a) 2050783 b) 2070873 c) 1980873 d) 2080783
Answer : d) 2080783
Solution :
Let X be the value of ?.
Then, 3437001 - X = 1356218
-X = 1356218 - 3437001
X = 3437001 - 1356218 = 2080783
Question 4
6 + 66 + 666 + ? = 744.06
a) 6.16 b) 6.06 c) 6.96 d) 5.96
Answer : b) 6.06
Solution :
Let X be the value of ?.
Then, 6 + 66 + 666 + X = 744.06
738 + X = 744.06
X = 744.06 - 738 = 6.06