1\21*7.47+1\21*5.63+13.1*20\21

Question

1\21*7.47+1\21*5.63+13.1*20\21

Answer 1

1/21* 7,47 +1/21 *5,63 + 13,1 *20/21        1/21(7,47 + 5,63) +13,1*20/21 =
1 /21  *13,1+ 13,1  *20/21   = 13,1(1/21 +20,21) = 13,1 *1    = 13,1