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Put 12 marbles in rows. Try rows of 4 — all fit exactly. Try rows of 5 — 2 are left over.

This is Chapter 5, Prime Time, in your NCERT Maths book. Let's make it easy first.

What you will learn

• Factors — numbers that divide a number exactly.
• Multiples — the numbers you reach counting in equal steps.
• Primes — numbers with exactly two factors: 1 and itself.
• Composites — numbers with more than two factors.
• Divisibility — a quick test, no dividing needed.
• Common factors — numbers on two factor lists at once.

Need a quick recap?

These Track Zero lessons help. Open one again if you are not sure.

• Counting — matching amounts one to one.
• Comparing — telling more, less, or equal.