Can you convert the number zero(0) into a positive number using just one mathematical operator ?

How many triangles can you find in this given picture?

Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

Given below is simple addition with a defined pattern pattern:
7 + 7 = 2
8 + 8 = 4
8 + 5 = 1
6 + 9 = 3
10 + 11 = 9

Can you analyze the pattern and find out the answer for:

4 + 9 = ?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

What do you get if you add 2 to 100 four times?

You need to move three matchsticks to form three squares. Can you do it?

I am something people love or hate. I change peoples appearances and thoughts. If a person takes care of them self I will go up even higher. To some people I will fool them. To others I am a mystery. Some people might want to try and hide me but I will show. No matter how hard people try I will Never go down. What am I?

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

A boy was locked in a room by some robbers. All that is in the room is a piano, a calendar, and a bed. The room is locked from the outside. What does he eat, drink, and how does he escape and get out?