BODMAS = B - Brackets

                    O - Of

                    D - Division

                    M - Multiplication

                    A - Addition

                    S - Subtraction

The given expression is  $45÷9+8\times 5-45$

According to BODMAS, Division is done before Multiplication, Addition and Subtraction.

Hence, $"45÷9"$ is the operation that needs to be performed first. 

50 Tens 5 Ones = $50\times 10+5\times 1=500+5=505$

4 Hundreds, 9 Tens 9 Ones = $4\times 100+9\times 10+9\times 1=400+90+9=499$

$505>499$

Hence, 50 Tens 5 Ones is greater.

$\stackrel{1}{\text{/}2}\stackrel{9}{\text{/}0}\stackrel{9}{\text{/}0}\stackrel{13}{\text{/}3}\underset{–}{-1897}\underset{–}{106}$

$15\times 7=105$

$15+7=22$

$105\underset{–}{-22}83$

105 is 83 more than 22.

Two lakhs two hundred = 2,00,200

When 2,00,200 is subtracted from 2,22,222, we have:

$2,22,222\underset{–}{-2,00,200}\underset{–}{22022}$

When 22022 is divided by 2, we get:

$\frac{22022}{2}=11011$

Weight of each pack of chips = 250 g

Total weight of the big pack =  5000 g

No of packets of chips with 250 g of chips

= $5000÷250$

= $\frac{5000}{250}$

= $20packs$
 

Monday to Friday = 5 days

Distance travelled by A in 1 day

Distance travelled by B in 1 day

Total distance travelled by A in 5 days
= $2\times 5=10km$

Total distance travelled by B in 5 days
= $4\times 5=20km$

So, B travels $(20-10)$ km = 10 km more than A from Monday to Friday.

4040404 doubled means multiplied by 2. 

$4040404\times \underset{–}{2}\underset{–}{8080808}$

8080808, when divided by 2, means it is halved.

$\to$ $8080808÷2$

= $\frac{8080808}{2}$ 

=$4040404$

$55555÷5$

= $\frac{55555}{5}$

= $11111$

Now,

$=11111\underset{–}{-1111}\underset{–}{10,000}=10thousands$

Number of children in class 5 = $43$

Number of children in class 6 = $29$

Total number of children = $43+29=72$

Number of buses = $4$

Number of children in each bus

= $72÷4$
$$\begin{array}{c}18\\ 472\\ -\underset{–}{4}2\\ 32\\ -\underset{–}{32}\\ 0\end{array}$$Therefore, number of children in each bus is 18.