Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

What is the largest number you can write with just 3 digits?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not rounded numerals equals 24.

What number divided by 4 is the same as that number minus 4?

If a zookeeper had 100 pairs of animals in her zoo, and two pairs of babies are born for each one of the original animals, then (sadly) 23 animals don’t survive, how many animals do you have left in total?

In the image below, can you find the value of an angle(y)

I am an odd number. Take away a letter and I become even. What number am I?

Rectify the following equality 101 - 102 = 1 by moving just one digit.

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

A cricket has 6 legs, a squirrel has 4 legs and a spider has 8 legs.

In a local zoo, it was found that the total number of legs is 612. Also, there are equal number of each of the above animals/insects.

Can you find out how many animals are there in the zoo?