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Chance is a number. This chapter shows you how to find it.

This is Chapter 14, Probability, in your NCERT Maths book.

What you will learn

• Chance = wanted ÷ all. The main rule of the chapter.
• Two spinners, one grid. Write each result as a pair.
• Two dice, 36 pairs. The chance of sum 7 is not 1/11.
• 0, 1, or in between. A quick check for wrong answers.
• Equal chance. Count the paper slips, not the numbers on them.
• "Not" means 1 minus. A shortcut.
• "Or" means count each one once.
• All together. One question, every step.
• Coins. List every result in order.
• A pack of 52. Count the cards that fit.
• Number words. Prime, square, between.
• Kept out. A marble kept out lowers the total by 1. It lowers the count of its own colour by 1.

Need a quick recap?

These Class 9 lessons help. Open any shaky one before you start.

• Counting what happened — chance from real tries.
• Counting what could happen — chance from the set-up.
• When the two disagree — real tries wobble a little.
• Two things at once — a table of pairs.
• A tree of results — pairs drawn as branches.