1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

10+10 and 11+11 can give you the same answer.

Explain how?

What Does this text mean:

important=important

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

I have two sand hourglasses:
1. A 7 minute one and
2. An 11-minute one.

Using just these 2 sand hourglasses, how can I measure time as 15 minutes?

Prove that twice of ten is the same as twice of eleven.

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

Find the next number in the sequence

1, 2, 6, 21, 88, __?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain