If you are doing 4 sets of 10 repetitions of air squats you are doing x which equals to air squats

4x10=30

Explanation:

You can easily know it's multiplication when you see the sign. It gives you the number but you have to plug it in. So once you plug in the numbers then you should get either 4x10 or 10x4 which means both is equal to 40

sonar - device which is used to find the submit submarines, sankalp ship. sonar waves consists of a transmitter and detector which are installed in the observation centre on board of a ship. the ultrasonic waves are sent into the sea at high frequency about 1000 khz in all direction.