We need: April − March.
That is: \(2,16,813 - 2,12,583\).
- Write in columns (ones, tens, hundreds, thousands, ten-thousands, lakhs):
\[\begin{aligned}
&\phantom{-}\;2\;16\,813\\
&-\;2\;12\,583
\end{aligned}\]
- Ones: \(3 - 3 = 0\).
- Tens: \(1 - 8\) cannot do. Borrow 1 hundred (\(=10\) tens).
Now tens become \(11\) and hundreds above become \(7\).
\(11 - 8 = 3\).
- Hundreds: after borrowing, \(7 - 5 = 2\).
- Thousands: \(6 - 2 = 4\).
- Ten-thousands: \(1 - 1 = 0\).
- Lakhs: \(2 - 2 = 0\).
So the result is \(04,230\), which is \(4,230\).
Answer: \(4,230\) children.