Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

Spot 5 differences in two Christmas tree below:

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

You are mixing a mixture of cement and Sand with five gallons of water. You have a garden hose giving you all the water you need. The problem is that you only have a four-gallon bucket and a seven-gallon bucket and neither has graduation marks. Find a method to measure five gallons.

In particular commonwealth games, a female participant won silver and gold medals for a single event.

How can this be possible?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?