1. Introduction: Numericals Are Not a New Topic
You have spent this whole chapter meeting ideas one at a time. Current. Potential difference. Resistance. Ohm's Law. Resistors joined in series and in parallel. Electric power. The heating effect of current. Each one came with its own formula.
A "numerical" just asks you to use those formulas together to answer a real question — how much current, how much heat, how big a bill? Nothing new is being taught here. The only new skill is stitching the formulas into a chain.
Here is the part that trips people. Most students who lose marks in numericals do not lose them at the arithmetic. They lose them at the first move — they grab a formula before they have understood what the question gives them and what it wants. They divide when they should multiply. They forget that "10 minutes" is not "10 seconds". They use the series rule on a parallel circuit.
So this lesson is not about doing harder sums. It is about doing the first move right, every single time. Get the picture and the plan correct, and the numbers fall out on their own.
Stop scrolling. Try this in your head before reading on: a fan runs on a current of . The supply is . Do you have enough to find the fan's power? (Yes — power is , and you have both and .)