Question

Вычисли рационально. 23+89+77; 44+77+56; 223+389+277; 144+578+256; 123+289+177; 544+278+156.

Answer 1

23 + 89 + 77 = (23 + 77) + 89 = 100 + 89 = 189

44 + 77 + 56 = (44 + 56) + 77 = 100 + 77 = 177

223 + 389 + 277 = (223 + 277) + 389 = 500 + 389 = 889

144 + 578 + 256 = (144 + 256) + 578 = 400 + 578 = 978

123 + 289 + 177 = (123 + 177) + 289 = 300 + 289 = 589

544 + 278 + 156 = (544 + 156) + 278 = 700 + 278 = 978