I need an intervention for a 1st grade math student [View All]

I have a little boy in the class I am student teaching who got a 23 percent on the first test I gave. I am so upset because obviously this kid did not get what I taught.
Out of 23 kids, one was absent, 10 got 100%, two earned a 96%, five more had 90%, two earned 86%, one 76% and one 66%. The last one didn't finish the test she simply drifted off as usual, but got a perfect score on the ones she did.

But the little boy who got 23% was consistant. The test was simple addition. For instance 2+7=15, 8+2=17,3+5=12, 1+3=6, 6+4=15.... do you see the pattern? I have no idea why this is happening.

I can't send this test home to his parents without some idea of how to help him. He does fine with reading and is a sharp kid otherwise, though he seems to have a lot of anxiety about being at school. He goes to the nurses office a lot.


HELP!