Page 72 - ICSE Math 5

2. Solve the following.
(a) Write the greatest 3-digit number and the product of its prime factors.

(b) Write the common factors of 18, 28, 46 and 58.
(c) Find the prime factors of 100 and 63 by factor tree method.
(d) Write the greatest number which can divide 366 and 579.

3. Find whether the given numbers are divisible by 2, 3, 4, 5, 6, 8, 9, 10 and 11. Put a
tick (), if the numbers are divisible and a cross (), if they are not.

Number 2 3 4 5 6 8 9 10 11
132

184
990

7,568
12,210

4. Find out whether the first number is a factor of the second number or not. Write Yes or
No.

(a) 44; 2,816 (b) 5; 225

(c) 92; 2,281 (d) 9; 981

5. Find the H.C.F. of the following numbers by listing method and common division method.

(a) 75 and 260 (b) 240 and 318
(c) 187, 231 and 275 (d) 165, 350 and 425

6. Find the L.C.M. of the following numbers by listing and common division method.

(a) 52 and 128 (b) 45 and 120
(c) 12, 143 and 220 (d) 12, 48 and 96

7. The L.C.M. of 25 and 65 is 325. Find their H.C.F.

8. The L.C.M. of two numbers is 1,344 and their H.C.F. is 4. If one of the numbers is 84, find
the other number.

Values and Life Skills

On the World Environment Day, the volunteers of an NGO planted trees. The total number of
trees planted by them is the smallest number that can be formed using the digits 3, 6, 4, 0, and
5. How many trees did they plant in all? Is the number of trees planted a multiple of 3? Is it good
to plant trees? Comment.

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