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SAI International School
Sub – Mathematics
Class - IV
Topic – TIME
Sub topic – Regrouping of time
The regrouping of time is useful when we have two different units of time in the
same problem. Let us take the help of some examples to understand.
Example 1: What is the value of A in given problem?
12 hours 75 minutes = A hours 15 minutes
In order to get the answer we need to do the following steps:
Step 1: In both the sides of the problem, we have the values of minutes.
Step 2: The value of minutes in Left Hand Side (LHS) of the problem is greater
than that in Right Hand Side (RHS).
75 minutes > 15 minutes
We know that, 60 minutes = 1 hour
So, 75 minutes = 60 minutes + 15 minutes
= 1 hour + 15 minutes
Step 3: The LHS can now be written as
12 hours 75 minutes = 12 hours + 75 minutes
= 12 hours + 1 hour + 15 minutes
= 13 hours + 15 minutes
= 13 hours 15 minutes
Therefore, the required answer is 13.
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