Does anyone know what this function is!!!! HELP

Hi guys,
Does anyone know what this equation is? {=SUM(IF($C$12:$L$12>0,($C$12:$L$12/$C$13:$L$13)*C44:L44*$C$13:$L$13))/$M$13}
so the {} before the equal sign is in the equation and it still computes its so weird. Also once I click on the equation to see the highlighted cells it refers to the {} go away and now it shows up as VALUE!. like wtf is this? When I put the {} back it doesnt work like I have to close the workbook and reopen to see the number it computes. can someone help me here. is like maybe explain what its doing and how I can fix it.
Thank you,
Your Friend!!

The { } indicates it is an Array formula : the formula is entered into the cell as

=SUM(IF($C$12:$L$12>0,($C$12:$L$12/$C$13:$L$13)*C44:L44*$C$13:$L$13))/$M$13 (no { } brackets)

THEN

HOLD down CTRL+SHIFT then hit ENTER

(CtrL+Shift+Enter)

If this is done correctly, the {.........} will appear round the formula

To see how it works highlight cell then "Evaluate Formulas" on the "Formula" ribbon,

Click "Evaluate" and it will step through the calculation.

Thank you guys,
Problem solved. I appreciate the help this forum is awesome!,
:-)