Решебник по математике 5 класс Ткачева рабочая тетрадь | Страница 21

\[\boxed{\mathbf{1.}}\]

\[1)\]

\[2)\ \]

\[3)\ \]

\[\boxed{\mathbf{2.}}\]

\[1)\ 3 + 497 = 497 + 3 = 500\]

\[2)\ 5 + 2038 = 2038 + 5 = 2043\]

\[\boxed{\mathbf{3.}}\]

\[1)\ (184 + 239) + 61 =\]

\[= 184 + (239 + 61) =\]

\[= 184 + 300 = 484\]

\[2)\ (500 + 342) + 158 =\]

\[= 500 + (342 + 158) =\]

\[= 500 + 500 = 1000\]

\[3)\ 584 + (116 + 258) =\]

\[= (584 + 116) + 258 =\]

\[= 700 + 258 = 958\]

\[4)\ 726 + (274 + 318) =\]

\[= (726 + 274) + 318 =\]

\[= 1000 + 318 = 1318\ \]

\[\boxed{\mathbf{4.}}\]

\[1)\ 37 + 206 + 163 =\]

\[= (37 + 163) + 206 =\]

\[= 200 + 206 = 406\]

\[2)\ 621 + 257 + 143 + 79 =\]

\[= (621 + 79) + (257 + 143) =\]

\[= 700 + 400 = 1100\]

\[3)\ 152 + 369 + 31 + 48 =\]

\[= (152 + 48) + (369 + 31) =\]

\[= 200 + 400 = 600\]

\[4)\ 256 + 0 + 483 + 244 + 117 =\]

\[= (256 + 244) + (483 + 117) =\]

\[= 500 + 600 = 1100\]