Question 13 Marks
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Answer the following : (3 mark each)
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12 questions · timed · auto-graded
Question 23 Marks
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Question 33 Marks
How will you show that $51$ is a composite number and $19$ is a prime number?
Answer
View full question & answer→$51 = 1 \times 51 , 3 \times 17$ has more than $2$ factors, so $51$ is a composite number
$19 = 1 \times 19 ,$ has only $2$ factors, so $19$ is a prime number.
$19 = 1 \times 19 ,$ has only $2$ factors, so $19$ is a prime number.
Question 43 Marks
List all the prime and composite numbers
$(a)$ between $45$ and $55,$
$(b)$ more than $70$ but less than $90.$
$(a)$ between $45$ and $55,$
$(b)$ more than $70$ but less than $90.$
Answer
View full question & answer→| Prime numbers | Composite numbers | |
| $(a)$ | $47, 53$ | $46, 48, 49, 50, 51, 52, 54$ |
| $(b)$ | $71, 73, 79, 83, 89$ | $72, 74, 75, 76, 78, 80, 81, 82, 84, 85, 86, 87, 88$ |
Question 53 Marks
Encircle the numbers which are divisible by $2$ and cross out the numbers which are not divisible by $2.$
$63\ 542\ 90\ 920\ 555\ 44\ 249\ 104\ 800$
$63\ 542\ 90\ 920\ 555\ 44\ 249\ 104\ 800$
Answer
View full question & answer→Number divisible by $2: 542, 90, 920, 44, 104, 800$
Numbers not divisible by $2: 63, 555, 249$
Numbers not divisible by $2: 63, 555, 249$
Question 63 Marks
Write $(a)$ all the factors $(b)$ factor pairs $(c)$ prime factors $(d)$ composite factors of $210.$
Answer
View full question & answer→$(a) 1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 42, 70, 105, 210$
$(b) (1, 210), (2, 105), (3, 70), (5, 42), (6, 35), (7, 30), (10, 21), (14, 15)$
$(c) 2, 3, 5, 7$
$(d) 6, 10, 14, 15, 21, 30, 35, 42, 70, 105, 210$
$(b) (1, 210), (2, 105), (3, 70), (5, 42), (6, 35), (7, 30), (10, 21), (14, 15)$
$(c) 2, 3, 5, 7$
$(d) 6, 10, 14, 15, 21, 30, 35, 42, 70, 105, 210$
Question 73 Marks
The multiples of a prime number except the number itself are composite. Explain it.
Answer
View full question & answer→$5$ is a prime number and its multiples $10, 15, 20, ...$ have more than two factors. So they are composite.
Question 83 Marks
There are $8$ pairs of twin primes between $1$ to $100.$ Tick (✔) them.
$(3, 5), (5, 7), (7, 9), (9, 11), (11, 13), (17, 19)$
$(29, 31), (31, 33), (41, 43), (59, 61), (71, 73), (97, 99)$
$(3, 5), (5, 7), (7, 9), (9, 11), (11, 13), (17, 19)$
$(29, 31), (31, 33), (41, 43), (59, 61), (71, 73), (97, 99)$
Answer
View full question & answer→$(3, 5), (5, 7), (11, 13), (17, 19), (29, 31), (41, 43), (59, 61), (71, 73)$
Question 93 Marks
Using the divisibility rules check whether the following numbers are divisible by $2, 3, 4, 5, 9$ or $10$. Write 'Yes' if the number is divisible and 'No', if it is not divisible.
| Divisible by | |||||||
| Numbers | $2$ | $3$ | $4$ | $5$ | $9$ | $10$ | |
| $(a)$ | $784$ | ||||||
| $(b)$ | $873$ | ||||||
| $(c)$ | $6318$ | ||||||
| $(d)$ | $55400$ | ||||||
Answer
View full question & answer→| Divisible by | |||||||
| Numbers | $2$ | $3$ | $4$ | $5$ | $9$ | $10$ | |
| $(a)$ | $784$ | Yes | No | Yes | No | No | No |
| $(b)$ | $873$ | No | Yes | No | No | Yes | No |
| $(c)$ | $6318$ | Yes | Yes | No | No | Yes | No |
| $(d)$ | $55400$ | Yes | No | Yes | Yes | No | Yes |
Question 103 Marks
boxe complete using division :
Question 113 Marks
boxe complete using division :
Question 123 Marks
boxe complete using division :
