How can you make number one disappear by adding something to it?

A girl has as many brothers as sisters, but each brother has only half as many brothers as sisters. How many brothers and sisters are there in the family?

What is more useful when it is broken?

I am the first thing you need while camping.
I am always with the person named Marcos Valencia and Carrick.
But Pogba Zlatan and Rooney think I am wasteful and do not need me.
I am the second to the last thing to add when you are making a patch.

What am I?

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

I’m tall when I’m young, and I’m short when I’m old. What am I?

Can you find the missing number in the third row?
35 20 14
27 12 18
5 2 ?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?