Question 825036
<pre>Underline them:

<u>6,4</u>,1,2,2,8,7,<u>4,2</u>,1,<u>5,3</u>,<u>8,6</u>,2,2,1,4,1,3,5,<u>8,6</u>

Answer: There are five. (6,4), (4,2), (5,3), (8,6) and (8,6)  

Note: We did not underline (1,3) or (3,5) because their 
difference is 1-3 = 3-5 = -2, not 2.

To find the difference between two numbers, it's always 
"first minus second", never "second minus first".

Edwin</pre>