All natural numbers including '0' form the whole numbers in mathematics. Whole numbers are the basic counting numbers. Whole numbers include positive integers along with 0.

Steps: 2 Marks
Answer: 1 Mark
One and half hours = 60 + 30 = 90 min

In 15 minutes, he types 45 words
He takes 5 minutes of break to align the paper.
So, the total number of words typed by him in 20 minutes = 45
Now, 90=(20+20+20+20)+10

So, in 80 minutes he can type 45 × 4 = 180 words
The number of words he can type in the next 10 minutes= $\frac{45}{15}\times 10=30$

So, total number of words he will type = 180 + 30 = 210 words.

Predecessor: 1 Mark
Successor: 1 Mark
Predecessor = Number - 1
$\therefore$ the three predecessors of 444 are: 
444 - 1 = 443,
443 - 1 = 442 and
442 - 1 = 441

Successor = Number +1
$\therefore$ the three successors of 444 are: 
444 + 1 = 445,
445 + 1 = 446 and
446 + 1 = 447

Steps: 2 Marks
Answer: 1 Mark
In two weeks, Rohit's total income = Rs. (26700 + 32800) = Rs. 59500

In two weeks, Shikhar's total income = Rs. (27300 + 31600) = Rs.58900

So, after deduction Rohit's income = Rs. 59500 - 3900 = Rs.55600

After deduction Shikhar's income = Rs (58900 - 4100) = Rs. 54800.

The difference in the incomes = Rs. (55600 - 54800) = Rs.800

Hence, Rohit's income is Rs. 800 more than Shikhar's income.

Steps: 1$\times$2=2 Marks
Answer: 0.5$\times$2=1 Mark
a) By distributive law

406$\times$516 = (400 + 6)$\times$(500 + 16)
= 200000 + 96 + 6400 + 3000 = 2,09,496

b) By distributive law
8 $\times$291$\times$125=(4×2)$\times$(290+1)$\times$(25× 5)=(25× 4)$\times$(5$\times$2)$\times$(290+1)
= 100 $\times$ 10 $\times$ (290+1) = 1000 $\times$ (290+1)
= 290000 + 1000 = 291000

Solution: 1 Mark
Example: 1 Mark
When we perform the arithmetic operations like addition and subtraction on whole numbers, the result is also a whole number. For e.g. Let us take two numbers as 12 and 16. When we perform addition,

12 + 16 = 28

When we perform multiplication,

12 $\times$ 16 = 192; the result of above operations is a whole number.

Whereas when we subtract these numbers, the result may or may not be a whole number.

E.g. 16 - 12 = 4, 4 is a whole number but 12 - 16 = -4, -4 is not a whole number.

Similarly, 16$÷$12 = 1.33, this is again not a whole number.

Steps: 2 Marks
Formula: 1 Mark
Answer: 1 Mark
Mahesh bought a bicycle for Rs. 2500.

Repairing cost = Rs. (82 + 20) = 80+2+20 = 100+2 = Rs.102

Total expenses on the bicycle = Rs. (2500 + 102) = 2500+100+2 = 2600+2 = Rs.2602

Profit = (Selling Price - Cost Price) = Rs. (3500 - 2602) = 3500-2600-2 = 900-2 = Rs. 898 

Application: 2 Marks
Steps: 1 Mark
Answer: 1 Mark
This pattern is like this:-

$45\times 9+2=407$

$456\times 9+3=4107$

$4567\times 9+4=41107$

For next three lines, it would be like this-
As we can see in the pattern, the number of digits is incremented by 1, and the units digit is the successor of the previous number. 
Also, the number which we are adding to the product is incremented by 1.
Using distributive property we can make the calculations simpler for the following,

$45678\times 9+5=45678\times (10-1)+5$
$=456780-45678+5=411107$

$456789\times 9+6=456789\times (10-1)+6$
$=4567890-456789+6=4111107$

Steps: 3 Marks
Answer: 1 Mark
Given that:
The first term of the sequence = 100.
Now every odd number is 7 less than the previous one and every even number is 2 more than the previous one.
So the second term=100 + 2 = 102
Third term = 102 - 7 = 95
Fourth term = 95 + 2 = 97
Fifth term = 97 - 7 = 90
Hence, the fifth term of the sequence is 90.

Steps: 1 $\times$2 = 2 Marks
Answer: 1$\times$2 = 2 Marks
a) Payment for new car = Rs. 28800

Total number of months in five years $=12\times 5=60$

So, total payment in five years $=28800\times 60=Rs.1728000$

b) To get the highest result, Suresh put the largest digit in ten’s position and smaller digit's in the unit’s position.