var count_ex = [0 , 0, 0];
function mathMy(tab){
count_ex[0] += +$(this).text();
console.log(count_ex[0]);
$('.smeta_table:first .header .ex_col_remove span').text(count_ex[0]+'р');
}
$('.smeta_table:first .ex_col_remove .cost_T1 span').each(mathMy(0));