File_Open("input.csv")
for (#1 = 0; #1 < 4; #1++) {
    Goto_Line(#1+2)                             // line (starting from line 2)
    if (#1) {
        Search(",", ADVANCE+COUNT, #1)          // column
    }
    #2 = Num_Eval()                             // #2 = old value
    Del_Char(Chars_Matched)                     // delete old value
    Num_Ins(#2+100, LEFT+NOCR)                  // write new value
}
File_Save_As("output.csv", OK+NOMSG)