How do you go from 98 to 720 using just one letter?

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

It has horns but can’t beep. It is like to bleat but It is not a sheep. What is it?

Identify Me

Hint1: I am a god
Hint 2: I am a planet
Hint 3: measurer of heat

Mr. Buttons was all set to go to the village of Buttonland to meet his friend. So, he packed his bags and left for the village at 5 in the morning. Upon travelling on a road for miles, he came across a point where the road diverged into two. He was confused on which road to take. He gazed around and he saw two owls sitting on a branch. He thought he could ask for directions for the village from the two owls. So he went to the tree. There he saw a sign which read, "One owl always lies, and one is always truthful. They both fly away if you ask them more than 1 question."
Mr. Buttons was caught in the dilemma of what to ask? And from which owl to ask, since he only had one question. What should Mr. Buttons ask?

What does below Rebus say?

XLR8

Can you start the fire using two pieces of wood?

How can one talk without saying a single word?

What does this rebus mean?

O
N
C
E
TIME

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13