Greetings #!#How to do wish

Soham received 40 messages on his birthday. Of these 90% were birthday greetings. How many other messages did he get, besides the greetings ?

In a class, there are 45 students. On a new year eve, every student sends one greeting card to each of the other students. How many greeting cards were exchanged in all?

If the selling price of 8 greeting cards is equal to the cost price of 10 greeting cards gain or loss percent

Wish bone of birds is from