Lesson 8 of 9
Track quiz
Show on a big screenSix ideas, six checks. The table first, so you have somewhere to look back.
| Move | How it goes |
|---|---|
| Find factors | Divide by 1, 2, 3… List every one that fits exactly. |
| Find multiples | Count up in that step, again and again. |
| Spot a prime | Count the factors. Exactly two? Prime. |
| Spot a composite | More than two factors? Composite. |
| Check divisibility | Look at the last digit, or add up the digits. |
| Find common factors | List both. Circle the numbers on both lists. |
12 idlis are shared exactly, with none left over. Which number of friends works?
Which of these lists is made entirely of multiples of 6?
How many factors does a prime number have, exactly?
1 has exactly one factor: itself. What does that make it?
526 ends in the digit 6. Which of these is true about 526?
Which number is a factor of both 12 and 18?
Chapter 5 of your NCERT book is Prime Time. Its factor lists are the ones you built here. Read it, then try the exercises in your book.
Next: Perimeter and Area. The distance around a shape, and the space inside it.
Reveal every answer to finish this lesson.