90000

According to the question, sum of 9 and 2 = 9 + 2
Now, mutiplying it by 4, we have 4 \(\times\) (9 + 2)
which is the required expression.

89423 is the greatest number, because it has highest number of digits i.e. 5 and 100 is the smallest number, because it has least number of digits i.e. 3.

59785 is the greatest and 18 is the smallest.

For getting the smallest number, firstly we convert the numbers into ascending order.
The smallest 4-digit number is 2478.
For getting greatest number, firstly we convert the numbers into descending order.
The greatest 4-digit number is 8742.

Given, numbers are 819, 5240, 890 and 6249.
To convert numbers into descending order, we arrange numbers greatest to the smallest.
Now, descending order is 6249 > 5240> 890> 819.

Both 67454 and 78465 are five-digit numbers. So, we compare them by comparing the digits at ten thousand places. Since, 7> 6. So, 78465> 67454.

Both 97632 and 96543 have same number of digits i.e. five. Now, compare them by looking at the digits at ten thousand place, which is 9 for both the numbers.
Next, compare the second digit from the left. Here, it is 7 in 97632 and 6 in 96543.
Since, 7> 6
So, 97632> 96543

(a) Yes, prices can be arranged in increasing order as follows:
Rs.1788 < Rs.1897 < Rs. 2635 < Rs. 2854 < Rs. 3975
(b) Yes, prices can be arranged in decreasing order as follows:
Rs.3975 > Rs. 2854 > Rs. 2635 > Rs. 1897 > Rs. 1788.

Digits in ascending order are 0,1,2,3,4,5,6,7,8,9 and digits in descending order are 9,8,7,6,5,4,3,2,1, 0. Also, we know that 0 can never be taken at the leftmost place.
Keeping the digit 1 at thousands place, we can fill hundreds, tens and ones place digit by remaining digits.
Greatest number 

[Keeping the greatest digit i.e, 9, 8 and 7 at hundreds, tens and ones place]
Smallest number

[Keeping the smallest digit i.e. 0, 2 and 3 at hundreds, tens and ones place]

Given digits are 8, 5 and 1.
Here, descending order of the given digits is 8, 8, 5, 1. [∴ greatest digit 8 is taken twice]
∴ Greatest 4-digit number = 8851
and ascending order of the given digits is 1, 1, 5, 8. [∴ smallest digit 1 is taken twice]
∴ Smallest 4-digit number = 1158.

Given digits are 3, 8 and 7.
Here, descending order of the given digits is 8, 8, 7, 3. [∵ greatest digit 8 is taken twice]
∴ Greatest 4-digit number = 8873
and ascending order of the given digits is 3, 3, 7, 8. [∵ smallest digit 3 is taken twice]
∴ Smallest 4-digit number = 3378

Given digits are 4, 5, 6, 0, 7 and 8.
We can make many numbers by using these digits, five of them are as follows:
876540, 867540, 876450, 876045 and 867405
(a) After putting commas, numbers are as follows:
(i) 8,76,540 (ii) 8,67,540
(iii) 8,76,450 (iv) 8,76,045
(v) 8,67,405
(b) Ascending order of numbers is as follows:
867405 < 867540 < 876045 < 876450 < 876540
Descending order of numbers is as follows:
876540 > 876450 > 876045 > 867540 >  867405.

(i) From the given figure, it is clear that,
160> 159> 158> 154
∴ Ramhari is the tallest, because he has the height of 160 cm.
(ii) From the given figure, it is clear that,
154 < 158 < 159 < 160
∴ Dolly is the shortest, because she has the height of 154 cm.
We can arrange height from two types:
(a) Yes, we can arrange their heights in increasing order as follows: Dolly (154 cm) < Mohan (158 cm) < Shashi (159 cm) < Ramhari (160 cm).
(b) Yes, we can arrange their heights in decreasing order as follows: Ramhari (160 cm) > Shashi (159 cm) > Mohan (158 cm) > Dolly (154 cm).

1023 is required smallest four-digit number.

According to Indian system of numeration, 6,17,11,682.

We know that,
1 million = 1000000 (in digits)
= 10 \(\times\)100000 = ten \(\times\) one lakhs (in number name)
∴1 million = ten lakhs

We know that,
1 million = 1000000 (in digits) = 10 \(\times\) 100000
= ten\(\times\) hundred thousands
(in number name)
∴ 1 million = ten hundred thousands