Question 210890
To group digits 1 to 4 means to place small groups digits in parentheses whose sum will give you 100. 

SAMPLE: 

Let's say I was given digits 1 - 5 and given the same directions to find a sum of 15. 

This is what I would do: 

(1+2+3)+(4+5) = 6 + 9 = 15 

This is exactly what you must do in orde to find your sum of 100. 
Understand? This is what you must do with your question.