7. 456-184 527-519 731-403 166+334 292+468 440 + 196 360-60-30 670-10-70 720-200+50

Разберем каждый пример по отдельности: * [456 - 184 = 272] * [527 - 519 = 8] * [731 - 403 = 328] * [166 + 334 = 500] * [292 + 468 = 760] * [440 + 196 = 636] * [360 - 60 - 30 = 300 - 30 = 270] * [670 - 10 - 70 = 660 - 70 = 590] * [720 - 200 + 50 = 520 + 50 = 570]