Crazy Math - math challenge

Crazy Math is created in order to give yourself a chance of being challenged with simple to complicated additions in Math.
The rule of this game is you have to choose the only right answer in the 2 given options to solve random Math sum problems within only 5-6 seconds. The highest number of components in an addition is 8, implying that you have maximum 6 seconds to give the right answer.
How will you score? Easy!
If the addition contain two components, you get 1 score if answering correctly. For example: if the screen shows: 2+3, you press 5 in the two given choices, you will get 1 score for this question.
Similarly, you gain 7 score for solving accurately 8-component addition. To illustrate, if the question is: 1+2+3+4+...+7+8, you choose the answer of 35 and then get 7 score for this questions.