Class 3    Math    Identify a number
Identifying the missing numbers based on conditions

Question: Sum of four numbers is 57, where largest number is 21 and lowest number is 11. If we subtract 8 from the largest number then we can find third number. Identify fourth number ?

Answer: This question is also simple addition/subtraction example. Only trick in this question is to identify the third number, which is 8 less than the largest number. So the third number is 21 − 8 = 13

Now the question is to identify the fourth number, which we can identify by adding first three known number and then subtract this from the total numbers.

The equation will look like something shown below:

     57 = 21 + 11 + 13 + X (fourth number)
     57 = 45 + X
     X = 57 − 45
     X = 12

Hence, the fourth number is 12