Page 44 - Math 7

Operations on Whole Numbers

Creative Section - B

6. a) Find the least number which is exactly divisible by 12, 16, and 24.
b) Find the smallest number which is when divided by 25, 30, and 75 leaves
no remainder.

7. a) If three buckets of capacities 10l, 12l, and 15l can fill a drum in exact number
of fillings, find the least capacity of the drum.
b) Three measuring rods are 40 cm, 50 cm and 80 cm long. Find the shortest
length of cloth which can be measured exactly by any one of these rods.
c) After travelling every 400 km, a motorcycle needs to fill petrol. After every
1600 km, it needs to change mobil. After every 2400 km, it needs servicing.
If these works are done together on a day. After how many kilometres of
travelling are all theses works repeated again ?
8. a) Three bells ring at an interval of 10, 15, and 20 minutes respectively. If they
all ring together at 6:00 a.m., at what time do they ring again together?
b) From Kathmandu bus park, buses moved to Pokhara in an interval of every
30 minutes, Birgunj in every 45 minutes, and Mahendranagar in every
1 hour. If the buses move to these places at the same time at 3:00 p.m. at
what time do the buses again move from the bus park at a time?
9. a) Find the least number which leaves a remainder 5 when it is divided by
any one of the numbers 10, 12 , and 15.
b) Find the least number which leaves a remainder 4 when it is divided by any
one of the number 12, 16, and 24.
10. a) Find the least number with which when 5 is added, the sum is exactly
divisible by 12, 18, and 20.
b) Find the least number with which when 20 is added, the sum is exactly
divisible by 30, 40, and 60.
It’s your time : Project work!

11. Let's do the following activities and answer the given questions.
a) Let's take 4 green cards and 6 yellow cards.
(i) Divide these cards equally between your four friends. Is it possible?

(ii) Divide these cards equally between your three friends. Is it possible?
(iii) Divide these cards equally between your two friends. Is it possible?
(iv) What is the H.C.F. of 4 and 6?
b) Let's take the number of the following pairs of coloured card and repeat the
similar activities to find the H.C.F. of the each pair of numbers.
(i) 2 green and 4 yellow cards (ii) 6 green and 9 yellow cards

(iii) 8 green and 12 yellow cards (iv) 10 yellow and 15 green cards.

Vedanta Excel in Mathematics - Book 7 42 Approved by Curriculum Development Centre, Sanothimi, Bhaktapur