Page 197 - New Medley 4 Semester 1

Z Z Now, encircle the remaining numbers. Do you know the numbers which you
encircled? Yes! These are prime numbers up to 100.

All the numbers you crossed out are composite numbers.

In same way find prime numbers between 101 and 130.

Now, answer these questions

1. Write the pairs of twin primes up to 100.

2. Can you say seven consecutive composite numbers?

3. How many pairs of primes that differ by 10 you see in the above chart?

MATHS LAB ACTIVITY • Experiential Learning

Aim: To find the LCM using a 100-number chart
Materials: A 100-number chart and bindis of different colours

Method: Let us find the LCM of 6 and 8.

1. Take a 100-number chart.

2. Take few bindis of red colour. Paste one bindi in the
box of number 6.
1 2 3 4 5 6 7 8 9 10
3. Then, move 6 blocks
forward and paste
another bindi. Continue 11 12 13 14 15 16 17 18 19 20
this process till you
21 22 23 24 25 26 27 28 29 30
reach 100 or go out.
The numbers with these 31 32 33 34 35 36 37 38 39 40
bindis are multiples of
6. 41 42 43 44 45 46 47 48 49 50

4. Then, take few bindis
of green colour. Paste 51 52 53 54 55 56 57 58 59 60
one bindi in the block
of number 8. 61 62 63 64 65 66 67 68 69 70

5. Repeat the step 3 by 71 72 73 74 75 76 77 78 79 80
counting 8 blocks each
time. The numbers
81 82 83 84 85 86 87 88 89 90
with these bindis are
multiples of 8. 91 92 93 94 95 96 97 98 99 100

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