77метров
5км=50м
2700см=27м
50+27=77м
А(567 + 7843 =8410
2415 - 7843 = 10258
б) 88942 - 44701 =44241
88942 -17942 =71000
в)(830+243)-647=399
(1712+805)-647=1870
/х-21/ и 31 + 14 и 31= 25 и 31
/х-21/= 25 и 31- 14 и 31= 11 и 31
х= 11 и 31+ 21 и 31= 31 и 31= 1
1) 78 • 85 - 69 = 6 561
1) 78 • 85 = 6 630
2) 6 630 - 69 = 6 561
2) 78 • (85 - 69) = 1 248
1) 85 - 69 = 16
2) 78 • 16 = 1 248