In question 1)
The doubles fact is 2+2, and notice that
[tex]2+3=2+2+1=(2+2)+1[/tex]
Thus, you need to circle the plus sign below 2+3.
On the other hand,
[tex]2+1=2+2-1=(2+2)-1[/tex]
Therefore, you need to circle the minus sign below 2+1
Similarly, circle the plus sign below 2+4 and 4+5, and circle the minus sign below 3+2 and 4+3
