Question

calculati ,folosund factorul comun a) 13×5+13×21+13×40 b) 437×109-437×54+437×203 c)49×135-49×27+49×11 d)2011×5+211×7+211×49+211×39 e)2+4+6+8+10+12 f)13×17+13×25-42×11-2×41

Answer 1

$13 \times (5 + 21 + 40) = 13 \times 66 = 856 \\ b)437 \times (109 - 54 + 203) = 437 \times 258 = 112746 \\ c)49 \times (135 - 27 + 11) = 49 \times 119 = 5831 \\ d)211 \times (5 + 7 + 49 + 39) = 211 \times 100 = 21100$
e)2+4+6+8+10+12=32