It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

what does the below math rebus puzzle mean?

Count the number of balls in picture below:

What does this rebus means ?

PROG WORKRESS

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

What common phrase is represented by the below lines

Easy going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Medium going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Tough going:
Weak, 'I can't do it, I'm staying!'
Tough, 'Let's get going.'

Identify the 10 differences between the two given pictures.

Remove two matchsticks to make the below equation correct.

You are playing as white and given four rooks to checkmate the black king in four moves with the following rules 1. You can place one rook every move and ensure the black king should be in check position.2. After four moves the black king should be in the checkmate position.

There are nine letters in the below-given diagram. You have to form a nine-letter word using these letters.