Number System ICSE Class-6th Concise Selina Maths

Which is greater ?
(i) 45293 or 45427
(ii) 380362 or 381007
(iii) 63520 or 63250

Answer
(i) 45293 or 45427
We observe that both the numbers are of 5-digits.
And at the digits at leftmost and second place from the left are same.
But the digits at the third place from the left are different, the first number has 2 and the second number has 4.
Since 2 < 4
45427 is greater

(ii) 380362 or 381007
We observe that both the numbers are of 6-digits.
And at the digits at leftmost and second place from the left are same.
But the digits at the third place from the left are different, the first number has 0 and the second number has 1.
Since 0 < 1
381007 is greater
(iii) 63520 or 63250
We observe that both the numbers are of 5-digits.
And at the digits at leftmost and second place from the left are same.
But the digits at the third place from the left are different, the first number has 5 and the second number has 2.
Since 5 < 2
63520 is greater

Question 4.

By making a suitable chart, compare:
(i) 540276 and 369998
(ii) 6983245 and 6893254
Answer
(i) 540276 and 369998

5	4	0	2	7	6
3	6	9	9	9	8

Clearly, both the numbers have equal number of digits i.e. 6
And at the leftmost, the first number has 5 and the second number has 3.
Since 5 > 3
540276 is greater.
(ii) 6983245 and 6893254

6	9	8	3	2	4	5
6	8	9	3	2	5	4

Clearly, both the numbers have equal number of digits i.e. 7
And at the leftmost, both have the same digit i.e. 6
And at the second place from the left, the first number has 9 and the second number has 8.
Since 9 > 8
6983245 is greater.

Question 5.

Compare the numbers written in the following table by writing them in ascending order:

	5	4	3	2	9	7	2
2	3	1	0	6	2	9	3
	5	2	2	3	7	9	1
2	3	1	8	2	6	3	4
5	4	3	4	4	7	8	2

Answer
The given number in ascending order are as :
54344782 > 243182634 > 23106293 > 5432972> 5223791

5	4	3	4	4	7	8	2
2	3	1	8	2	6	3	4
2	3	1	0	6	2	9	3
	5	4	3	2	9	7	2
	5	2	2	3	7	9	1

Question 6.

Use table form to compare the numbers in descending order : 5,43,287; 54,82,900; 27,32,940; 43,877 ; 78,396 and 4,999
Answer
The given numbers in descending order are as :

			4	9	9	9
		4	3	8	7	7
		7	8	3	9	6
	5	4	3	2	8	7
2	7	3	2	9	4	0
5	4	8	2	9	0	0

4, 999 < 43, 877 < 78, 396 < 5, 43, 287 < 27, 32, 940 < 54, 82, 900

Question 7.

Find the smallest and the greatest numbers in each case given below:
(i) 983, 5754, 84 and 5942
(ii) 32849, 53628, 5499 and 54909.
Answer

(i) 983, 5754, 84 ahd 5942
Since 84 has the least number of digits.
84 is the least smallest whereas 5754 and 5942 have the maximum number of digits.

Out of 5754 and 5942, 5942 is greater.
5942 is the greatest and 84 is the smallest.
(ii) 32849, 53628, 5499 and 54909.
Since 5499 has the least number of digits.
5499 is the smallest
Whereas 54909 and 53628 have the maximum number of digits. Out of 54909 and 53628, 54909 is greater.
54909 is the greatest and 5499 is the smallest

Question 15.

Find the sum of the largest and the smallest four-digit numbers:
Answer
Largest four-digits number = 9,999
Smallest four digits number = 1,000
Sum of the above = 9, 999 + 1,000 = 10,999.

Question 16.

Find the difference between the smallest and the greatest six-digits numbers.
Answer
Greatest six-digits number = 9, 99, 999
Smallest six-digits number = 1,00,000
Difference between greatest and smallest = 9, 99, 999 – 1, 00, 000 = 8, 99, 999

Question 17.

(i) How many four digit numbers are there between 999 and 3000 ?
(ii) How many four digit numbers are there between 99 and 3000 ?
Answer
(i) Four digit numbers between 999 and 3000 = 2999 – 999 = 2000
(ii) Four digit numbers between 99 and 3000 = 2999 – 999 = 2000

Question 18.

How many four digit numbers are there between 500 and 3000 ?
Solution:
Four digits numbers between 99 and 3000 = 2999 – 999 = 2000

Question 19.

Write all the possible three digit numbers using the digits 3, 6 and 8 only; if the repetition of digits is not allowed.
Answer
All the three digits number using 3, 6, and 8 when repetition is not allowed, can be :
368, 386, 638, 683, 836, 863.

Question 20.

Make the greatest and the smallest 4-digit numbers using the digits 5, 4, 7 and 9 (without repeating the digits) and with the condition that:
(i) 7 is at unit’s place.
(ii) 9 is at ten’s place
(iii) 4 is at hundred’s place

Answer
(i) 7 is at unit’s place
The smallest 4-digit number using the digits 5, 4, 7 and 9, and keeping 7 at unit’s place = 4597
The greatest 4-digit number using the digits 5, 4, 7 and 9 and keeping 7 at unit’s place = 9547
(ii) 9 is at ten’s place
The smallest 4-digit number using the digits 5, 4, 7 and 9 and keeping 9 at ten’s place = 4597
The greatest 4-digit number using the digits 5, 4, 7 and 9 and keeping 9 at ten’s place = 7594
(iii) 4 is at hundred’s place
The smallest 4-digit number using the digits 5, 4, 7 and 9 and keeping 4 at hundred’s place = 5479
The greatest 4-digit number using the digits 5, 4, 7 and 9 and keeping 4 at hundred’s place = 9475

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Exercise -1 B of Number System for ICSE Class-6th Concise Maths

Question 1.

Population of a city was 3, 54, 976 in the year 2014. In the year 2015, it was found to be increased by 68, 438. What was the population of the city at the end of the year 2015?
Answer
Population of a city in 2014 = 3,54, 976
Population increased in 2015 = 68, 438
Total population at the end of the year 2015 = 3, 54, 976 + 68, 438 = 423414

A = 7,43,000 and B = 8,00,100. Which is greater A or B ? And, by how much?
Answer
A = 7,43,000
B = 8,00,100
B is greater than A. (B > A)
Because = B – A
Since A = 7, 43, 000 and B = 800,100 and both the numbers have 6 digits.
And at the leftmost, the first number has 7 and the second number has 8.
Since 8 > 7
800, 600 > 7,43,000 (B > A)
B is greater than A by = 800, 100 – 7, 43, 000 = 57, 100

A small and thin notebook has 56 pages. How many total number of pages will 5326 such note-books have?
Answer
Number of pages in one notebook = 56 pages
Number of pages in 5326 notebooks = 5326 x 56 = 298256 pages

The number of sheets of paper available for making notebooks is 75,000. Each sheet makes 8 pages of a notebook. Each notebook contains 200 pages. How many notebooks can be made from the available paper ?
Answer
Number of sheets available = 75, 000
Number of pages obtained from one sheet = 8
Total number of pages obtained = 8 x 75, 000 = 6, 00, 000

Add 1, 76, 209; 4, 50, 923 and 44, 83, 947
Answer
1, 76, 209 + 4, 50, 923 + 44, 83, 947

Adding these values, we get = 51, 11, 079

A cricket player has so far scored 7, 849 runs in test matches. He wishes to complete 10, 000 runs ; how many more runs does he need ?
Answer
Score of cricket player = 7, 849 runs
Total scores he wish to complete = 10,000
Runs required = 10, 000 – 7, 849 = 2151

In an election two candidates A and B are the only contestants. If candidate A scored 9, 32, 567 votes and candidates B scored 9, 00, 235 votes, by how much margin did A win or loose the election ?
Answer
Scores of candidate A = 9,32,567
Scores of candidate B = 9,00,235
Candidate A win the election By margin = 9,32,567 – 9,00,235 = 32,332 scores

Find the difference between the largest and the smallest number that can be written using the digits 5, 1, 6,3 and 2 without repeating any digit.
Answer
The digits given are = 5, 1, 6, 3 and 2
The largest 5-digit number that can be formed using the digits 5, 1, 6, 3 and 2 = 65321
The smallest 5-digit number that can be formed using the digits 5, 1,6, 37and 2 =12356
Difference between 65321 and 12356
= 65321 – 12356 = 52,965

A machine manufactures 5,782 screws every day. How many screws will it manufacture in the month of April ?
Answer
Number of screws in one day = 5, 782
Number of days in April = 30 days
Number of screws in April = 5, 782 x 30 = 1,73,460

A man had ₹ 1, 57, 184 with him. He placed an order for purchasing 80 articles at 125 each. How much money will remain with him after the purchase ?
Answer
Money in hand = ₹ 1, 57, 184
Number of articles purchased = 80
Cost of one article = ₹ 125
Cost of 80 articles = ₹ 80 x 125 = ₹ 10,000

A student multiplied 8,035 by 87 instead of multiplying by 78. By how much was his answer greater than or less than the correct answer ?
Answer
Correct answer = 8,035 x 87 = 6,99,045

Question 12.

Mohani has 30 m cloth and she wants to make some shirts for her son. If each shirt requires 2 m 30 cm cloth, how many shirts, in all, can be made and how much length of cloth will be lefft ?

Answer
Total length of cloth available = 30 m or 30 x 100 = 3000 cm
Shirt made by using 2m 30cm (230 cm) cloth = 1
Shirts made by using 30 m cloth =  x 3000 = 13.04 = 13 shirts
Cloth required to make 13 shirts = 230 x 13 = 2990 cm or 29 m 90 cm
Hence, remaining cloth = 30 m – 29 m = 1m

Question 13.

The weight of a box is 4 kg 800 gm. What is the total weight of 150 boxes?>
Answer
Weight of one box = 4 kg 800 gm
Total weight of 150 boxes = 4 kg 800 g x 150 = 720 kg

Question 14.

The distance between two places A and B is 3 km 760 m. A boy travels A to B and then B to A every day. How much distance does he travel in 8 days?
Answer
Distance between two places = 3 km 760 m 3760 m
Distance among A to B and B to A = 2 x 3760 m = 7520 m
In 8 days he travelled = 7520 x 8 = 60160 m or 60 km 160 m

Question 15.

An oil-tin contains 6 litre 60 ml oil. How many identical bottles can the oil fill, if capacity of each bottle is 30 ml ?
Answer
Oil contained in a tin = 6 litre 60 ml = 6 x 1000 + 60 = 6060 ml
Capacity of each bottle = 30 ml
No. of bottled can be filled with 30 ml oil = 6060 ÷ 30 = 202 bottles

Question 16.

The scale receipt of a company in a certain year was ₹ 83, 73, 540. In the following year, it was decreased by ₹ 7, 84, 670.
(i) What was the sale receipt of the company during second year?
(ii) What was the total sale receipt of the company during these two years?
Answer
Sale receipt of the company during first year = ₹ 83,73,540
Sale decreased in second year = ₹ 7,84,670
(i) The sale receipt of the company during second year = ₹ 83,73,540 – ₹ 7,84,670

Question 17.

A number exceeds 8, 59, 470 by 3, 00, 999. What is the number?
Answer
First number = 8, 59, 470
Difference between second and first number = 3, 00, 999
Second number = 8, 59, 470 + 3, 00, 999 = 11, 60, 469

— End of Number System ICSE Class-6th Concise Solutions :–

Return to – Concise Selina Maths Solutions for ICSE Class -6 

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