\[\boxed{\mathbf{231\ (231)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ (176 + 343) - 243 =\]
\[= 176 + (343 - 243) =\]
\[= 176 + 100 = 276\]
\[2)\ (684 + 915) - 484 =\]
\[= 684 - 484 + 915 =\]
\[= 200 + 915 = 1115\]
\[3)\ (259 + 101) - 59 =\]
\[= 259 - 59 + 101 =\]
\[= 200 + 101 = 301\]
\[4)\ 1287 - (487 + 164) =\]
\[= 1287 - 487 - 164 =\]
\[= 800 - 164 = 636\]
\[5)\ 971 - (235 + 371) =\]
\[= 971 - 371 - 235 =\]
\[= 600 - 235 = 365\]
\[6)\ 5393 - (1393 + 158) =\]
\[= 5393 - 1393 - 158 =\]
\[= 4000 - 158 = 3842\]
\[\boxed{\ \mathbf{231}\mathbf{\ (199)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ 21\ 514 - 4328 = 17\ 186\]
\[т.е.\ на\ 17\ 186\ меньше.\]
\[2)\ 258\ 143 - 164\ 275 = 93\ 868\]
\[т.е.\ на\ 93\ 868\ больше.\]