West Bengal Board Solutions for Chapter: A Few Interesting Problems, Exercise 2: Exercise 2

If the sign $\text{'}÷\text{'}$ stands for the sign $\text{'}\times \text{'}$ and the sign $\text{'}+\text{'}$ stands for the sign $\text{'}÷\text{'}$ and the sign $\text{'}\#\text{'}$ stands for the sign $\text{'}+\text{'}$ then, let's write which of the following numbers will be the value of $2÷5+5\#100$.

If $7*1=64$ and $3*9=144$ then, let's write which one of the following will be the value of $5*6$

Let's write the value of $94\oplus 72$ from the following numbers if $84\oplus 72=45$ and $73\oplus 41=43$.

Why $142857$ is a revolving number?

$142857\times 1=142857$

$142857\times 2=285714$

$142857\times 3=428571$

$142857\times 4=571428$

$142857\times 5=$ _____

$142857\times 6=$ _____

Find $30$ using a one-digit number thrice.

$3^3+3=$ _____

Find $30$ using other one-digit number thrice except $3$.

Iman arranged $8$ number in two columns writing the numbers $1, 2, 3, 4, 5, 7, 8$ and $9$.

Try to get the same sum from the columns replacing only $2$ numbers.

Maria's father kept an envelope with some money on the table to buy books and went to office. Maria returned home and saw that $98$ is written on the envelope. So, she went to the bookshop and bought a book priced $₹92$. However, at the time of paying she saw that there was less than $₹92$ in the envelope. How did this happen? Think and write.

See the following problem. Write it in proper way.

$\begin{array}{cccc}& \mathrm{O}& \mathrm{N}& \mathrm{E}\\ +& \mathrm{T}& \mathrm{W}& \mathrm{O}\\ \mathrm{F}& \mathrm{O}& \mathrm{U}& \mathrm{R}\end{array}$