What common phrase is represented by the below lines

Easy going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Medium going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Tough going:
Weak, 'I can't do it, I'm staying!'
Tough, 'Let's get going.'

Four men were in a boat on the lake. The boat turns over, and all four men sink to the bottom of the lake, yet not a single man got wet! Why?

When is the top of a mountain similar to a savings account?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

What is the next number?

77, 49, 36, 18 ?

Spot 5 differences in two Christmas tree below:

Identify the next two numbers in this series.

101, 112, 131, 415, 161, 718, ???, ???

Rearrange the letters in "new door" to make one word.

Only one color, but not one size,
Stuck at the bottom, yet easily flies.
Present in sun, but not in rain,
Doing no harm, and feeling no pain.
What is it?

Can you solve below mathematical equation?

2^1234 - 2^1233