Have a query? Let us call you for FREE
X+91
E.g : 9884012345, 01123456789
Office hours: 9:00 am to 9:00 pm IST (7 days a week)
• What about you? Do you also find Maths difficult?
• What is the most difficult thing in your Maths books? ________
• What do you think is the easiest lesson? ________
Solution:
Disclaimer: The answer may vary from student to student based on his/her experience. It is highly recommended that the students prepare the answers on their own.
Find out: how much for a cup of tea?
Ask people and find out the cost of a cup of tea
• at a tea stall ____________
• at a hotel _______________
Solution:
Disclaimer: The purpose of this section is to make the students observe their surroundings. The answer may vary from student to student based on his/her experience. It is highly recommended that the students prepare the answers on their own.
If a person who runs a tea stall earns Rs 30 in a day, how much will he earn in 10 days? _____________
And in a month? _______________
How did you get the answer? Discuss.
Solution:
Earning of the man in 1 day = Rs 30
Earning of the man in 10 days = Rs 30 × 10
= Rs 300
We do it in the following manner:
1 times 30 is 30.
10 times 30 is 300.
Suppose there are 30 days in a month.
Earning of the man in a month or 30 days = Rs 30 × 30
= Rs 900
We do it in the following manner:
3 times 30 is 90.
30 times 30 is 900.
Hariya and Babu want to buy a handcart for Rs 300.
Who has to pay back more — Hariya or Babu? _____________
Solution:
Hariya took a loan of Rs 300 from a bank for 6 months to buy a handcart. He pays
Rs 51 every month to the bank.
Money paid back by Hariya to the bank in 1 month = Rs 51
Money paid back by Hariya to the bank in 6 months = Rs 51 × 6
= Rs 306
We do it in the following manner:
6 50 = 300
6 1 = 6
So,
So, Hariya paid Rs 306 to the bank after 6 months.
Babu took a loan of Rs 300 from Chunnilal for 6 months to buy a handcart. He paid
Rs 360 to Chunnilal after 6 months.
Thus, Babu has to pay back more than Hariya for buying the handcart.
I have 9 rickshaws of my own. I give the rickshaws on rent. each for Rs 20 a day. On Sundays I do not take any money for them.
• In a week how much does Kiran earn from one rickshaw?
Solution:
We know that there are 7 days in a week.
Earning of Kiran from 1 rickshaw per day = Rs 20
Earning of Kiran from 1 rickshaw for 7 days = Rs 20 × 7
= Rs 140
We do it in the following manner:
2 times 7 is 14.
20 times 7 is 140.
Now,
On Sunday, Kiran does not take any money for the rickshaws.
Therefore, earning of Kiran from 1 rickshaw for 6 days = Rs 140 − Rs 20
= Rs 120
We do it in the following manner:
So, Kiran will earn Rs 120 in a week from 1 rickshaw.
Do it mentally and write the answers.
Solution:
Look up the rate list to see today's rates. Help Kiran to find out the cost of the junk.
• How much will Kiran pay for 31 kg newspaper?
1 kg newspaper costs Rs 5. 30 kg cost Rs 5 × 30 = Rs 150. So for 31 kg she pays Rs _____.
• How much will Kiran pay for 42 kg newspaper?
• Also find the cost of:
(a) 22 kg of plastic
(b) 23 kg of waste paper
(c) 12 kg of iron
Rate-List | |
Kind of Junk | Price of 1 Kg |
1. Waste Paper | Rs 4/- |
2. Newspaper | Rs 5/- |
3. Iron | Rs 12/- |
4. Brass | Rs 170/- |
5. Plastic | Rs 10/- |
Solution:
• Kiran bought 1 kg plastic for Rs 10, but sold 1 kg plastic for Rs 12. How much money does she earn on selling 1 kg plastic? Rs _______
So, how much money does she earn for 63 kg? Rs _______
Solution:
Cost price of 1 kg plastic = Rs 10
Selling price of 1 kg plastic = Rs 12
Profit on selling 1 kg plastic = Rs (12 − 10)
= Rs 2
Profit on selling 63 kg plastic = Rs 2 × 63
= Rs 126
We do it in the following manner:
2 × 60 = 120
2 × 3 = 6
Hence, Kiran will earn Rs 126 on selling 63 kg plastic.
• How much money will Dinu pay for 32 kg iron?
• Kiran buys 1 kg iron for Rs 12 but sells it for Rs 14.
How much does she earn when she sells 32 kg iron? Rs _______
Solution:
• Cost of 1 kg iron = Rs 14
Cost of 32 kg iron = Rs 14 × 32
= Rs 448
We do it like this:
Add the numbers in the box
So, Dinu will have to pay Rs 448 for 32 kg iron.
I bought 1 kg newspaper for Rs 5, but sold it for Rs 6. How much money did I earn by selling 152 kg of newspaper? ________
Solution:
Cost of 1 kg newspaper = Rs 5
Selling price of 1 kg newspaper = Rs 6
Profit on selling 1 kg newspaper = Rs (6 − 5)
= Re 1
Profit on selling 152 kg newspaper = Re 1 × 152
= Rs 152
I earned Rs 152 on selling 152 kg of newspaper.
How much money will Dinu pay for 4 kg brass? _________
Guess the answer first.
Solution:
Cost of 1 kg brass = Rs 180
Cost of 4 kg brass = Rs 4×180
= Rs 720
We will do it as follows:
Add the numbers in the box
Thus, Dinu will pay Rs 720 for 4 kg brass.
First guess the answer and then calculate:
(a) 37 × 18 =
(b) 45 × 24 =
(c) 69 × 52 =
(d) 77 × 55 =
(e) 142 × 5 =
(f) 382 × 3 =
(g) 2 × 175 =
(h) 4 × 206 =
Solution:
(a)
Add the numbers in the box
(b)
Add the numbers in the box
(c)
Add the numbers in the box
(d)
Add the numbers in the box
(e)
Add the numbers in the box
(f)
Add the numbers in the box
(g).
Add the numbers in the box
(h)
Later she paid Rs 919 to the junk collectors. When she sold the junk she got these notes and coins from Dinu.
Now you make a record in her diary.
Find out how much she earned this time.
Solution:
We do it as follows:
5 notes of 100 rupee
5 100 = Rs 500
1 note of 50 rupee
1 50 = Rs 50
18 notes of 10 rupee
18 1 = 18
18 10 = Rs 180
9 notes of 20 rupee
9 2 = 18
9 20 = Rs 180
28 coins of 5 rupee
20 5 = 100
8 5 = 40
28 5 = Rs 140
Money I got = Rs 500 + Rs 50 + Rs 180 + Rs 180 + Rs 140
= Rs 1050
Money I earned = Rs 1050 − Rs 919
= Rs 131