By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

Spot 5 differences in two Christmas tree below:

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

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?

What's a single-digit number with no value?

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?

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

Find three numbers such that

* When we multiply three numbers, we will get the prime numbers.
* The difference between the second and the first number is equal to the third and second.

What does this mathematical rebus means ?