Стр.130 Часть 2 ГДЗ Дорофеев Миракова 4 класс (2023) (Математика)
Сравни.
$$40\,500\ \text{мм}^2$$ и $$4\ \text{дм}^2\ 50\ \text{см}^2$$
$$40\,500\ \text{дм}^2$$ и $$4\ \text{а}\ 5\ \text{м}^2$$
$$40\,500\ \text{м}^2$$ и $$40\ \text{га}$$
$$5\ \text{а}\ 40\,500\ \text{см}^2$$ и $$4\ \text{м}^2\ 500\ \text{см}^2$$Выполни действия.
$$18\ \text{м}\ 72\ \text{см} : 78\ \text{см}$$
$$74\ \text{т} : 250\ \text{кг}$$
$$29\ \text{км}\ 240\ \text{м} : 680\ \text{м}$$
$$21\ \text{км} : 840\ \text{м}$$
$$8\ \text{дм}\ 6\ \text{см} : 4\ \text{мм}$$
$$72\ \text{м} : 96\ \text{см}$$
$$8\ \text{т}\ 100\ \text{кг} : 9\ \text{кг}$$
$$9\ \text{га} : 36\ \text{м}^2$$Выполни вычисления, используя приём перегруппировки слагаемых.
$$238+577+162$$
$$530+750+170+250$$
$$197+315+203$$
$$633+1\,020+367+580$$Выполни вычисления, используя приём округления.
$$1\,299+517$$
$$230+6\,098$$
$$4\,709+164$$
$$195+4\,297$$
$$399+1\,096$$
$$1\,998+137$$Выполни вычисления удобным способом.
1) $$37+22+13+28$$
$$580-198$$
$$803-78$$
$$69+14+31+86$$
$$765-287$$
$$601-45$$2) $$15\cdot7\cdot2$$
$$4\cdot19\cdot25$$
$$6\cdot12\cdot20\cdot5$$
$$50\cdot9\cdot6$$
$$8\cdot25\cdot2$$
$$2\cdot18\cdot25\cdot2$$
$$25\cdot13\cdot4$$
$$6\cdot17\cdot15$$
$$4\cdot14\cdot50\cdot2$$3) $$3\,198-(270+198)$$
$$40\cdot25\cdot76$$
$$15\,000:(300\cdot2)$$
$$5\,000-(1\,607+303)$$
$$186\cdot5\cdot20$$
$$6\,400:(20\cdot50)$$
$$12\,024-(24+590)$$
$$8\cdot125\cdot37$$
$$15\,000:(300\cdot5)$$Найди значения выражений, используя приём последовательного умножения и деления.
1) $$25\cdot40$$
$$15\cdot28$$
$$25\cdot32$$
$$45\cdot12$$
$$48\cdot15$$
$$75\cdot20$$
$$16\cdot25$$
$$35\cdot24$$
$$18\cdot15$$
$$55\cdot12$$
$$15\cdot80$$
$$36\cdot20$$
$$16\cdot15$$
$$25\cdot64$$
$$24\cdot50$$2) $$450:6$$
$$270:18$$
$$240:16$$
$$690:15$$
$$1\,000:20$$
$$387:9$$
$$360:45$$
$$210:15$$
$$432:54$$
$$1\,000:25$$
$$288:8$$
$$432:48$$
$$315:45$$
$$385:55$$
$$1\,000:50$$
28.
$$40\,500\ \text{мм}^2 < 4\ \text{дм}^2\ 50\ \text{см}^2$$
$$40\,500\ \text{дм}^2 = 4\ \text{а}\ 5\ \text{м}^2$$
$$40\,500\ \text{м}^2 < 40\ \text{га}\ 5\ \text{а}$$
$$40\,500\ \text{см}^2 = 4\ \text{м}^2\ 500\ \text{см}^2$$
29.
$$18\ \text{м}\ 72\ \text{см} : 78\ \text{см} = 1872\ \text{см} : 78\ \text{см} = 24$$
$$74\ \text{т} : 250\ \text{кг} = 74\,000\ \text{кг} : 250\ \text{кг} = 296$$
$$29\ \text{км}\ 240\ \text{м} : 680\ \text{м} = 29\,240\ \text{м} : 680\ \text{м} = 43$$
$$21\ \text{км} : 840\ \text{м} = 21\,000\ \text{м} : 840\ \text{м} = 25$$
$$8\ \text{дм}\ 6\ \text{см} : 4\ \text{мм} = 86\ \text{см} : 4\ \text{мм} = 860\ \text{мм} : 4\ \text{мм} = 215$$
$$72\ \text{м} : 96\ \text{см} = 7200\ \text{см} : 96\ \text{см} = 75$$
$$8\ \text{т}\ 100\ \text{кг} : 9\ \text{кг} = 8100\ \text{кг} : 9\ \text{кг} = 900$$
$$9\ \text{га} : 36\ \text{м}^2 = 90\,000\ \text{м}^2 : 36\ \text{м}^2 = 2500$$
1.
$$238 + 577 + 162 = (238 + 162) + 577 = 400 + 577 = 977$$
$$197 + 315 + 203 = (197 + 203) + 315 = 400 + 315 = 715$$
$$530 + 750 + 170 + 250 = (530 + 170) + (750 + 250) = 700 + 1000 = 1700$$
$$633 + 1020 + 367 + 580 = (633 + 367) + (1020 + 580) = 1000 + 1600 = 2600$$
2.
$$1299 + 517 = (1300 — 1) + 517 = 1817 — 1 = 1816$$
$$195 + 4297 = (200 — 5) + (4300 — 3) = 4500 — 8 = 4492$$
$$230 + 6098 = 230 + (6100 — 2) = 6330 — 2 = 6328$$
$$399 + 1096 = (400 — 1) + (1100 — 4) = 1500 — 5 = 1495$$
$$4709 + 164 = (4700 + 9) + (160 + 4) = 4860 + 13 = 4873$$
$$1998 + 137 = (2000 — 2) + (140 — 3) = 2140 — 5 = 2135$$
3.
$$37 + 22 + 13 + 28 = (37 + 13) + (22 + 28) = 50 + 50 = 100$$
$$69 + 14 + 31 + 86 = (69 + 31) + (14 + 86) = 100 + 100 = 200$$
$$580 — 198 = 580 — (200 — 2) = 380 + 2 = 382$$
$$765 — 287 = 765 — 300 + 13 = 465 + 13 = 478$$
$$803 — 78 = 803 — 100 + 22 = 703 + 22 = 725$$
$$601 — 45 = 601 — 100 + 55 = 501 + 55 = 556$$
$$15 \cdot 7 \cdot 2 = (15 \cdot 2) \cdot 7 = 30 \cdot 7 = 210$$
$$50 \cdot 9 \cdot 6 = (50 \cdot 6) \cdot 9 = 300 \cdot 9 = 2700$$
$$25 \cdot 13 \cdot 4 = (25 \cdot 4) \cdot 13 = 100 \cdot 13 = 1300$$
$$4 \cdot 19 \cdot 25 = (4 \cdot 25) \cdot 19 = 100 \cdot 19 = 1900$$
$$8 \cdot 25 \cdot 2 = 8 \cdot (25 \cdot 2) = 8 \cdot 50 = 400$$
$$6 \cdot 17 \cdot 15 = 17 \cdot (6 \cdot 15) = 17 \cdot 90 = 1530$$
$$6 \cdot 12 \cdot 20 \cdot 5 = (6 \cdot 12) \cdot (20 \cdot 5) = 72 \cdot 100 = 7200$$
$$2 \cdot 18 \cdot 25 \cdot 2 = (2 \cdot 25 \cdot 2) \cdot 18 = 100 \cdot 18 = 1800$$
$$4 \cdot 14 \cdot 50 \cdot 2 = (4 \cdot 14) \cdot (50 \cdot 2) = 56 \cdot 100 = 5600$$
$$3198 — (270 + 198) = (3198 — 198) — 270 = 3000 — 270 = 2730$$
$$5000 — (1607 + 303) = 5000 — 1910 = 3090$$
$$12\,024 — (24 + 590) = (12\,024 — 24) — 590 = 12\,000 — 590 = 11\,410$$
$$40 \cdot 25 \cdot 76 = (4 \cdot 10) \cdot 25 \cdot 76 = (4 \cdot 25 \cdot 10) \cdot 76 = 1000 \cdot 76 = 76\,000$$
$$186 \cdot 5 \cdot 20 = 186 \cdot (5 \cdot 20) = 186 \cdot 100 = 18\,600$$
$$8 \cdot 125 \cdot 37 = (8 \cdot 125) \cdot 37 = 1000 \cdot 37 = 37\,000$$
$$15\,000 : (300 \cdot 2) = (15\,000 : 300) : 2 = 50 : 2 = 25$$
$$6400 : (20 \cdot 50) = 6400 : 1000 = 6\ (\text{ост. }400)$$
$$15\,000 : (300 \cdot 5) = (15\,000 : 300) : 5 = 50 : 5 = 10$$
4.
$$25 \cdot 40 = 1000$$
$$75 \cdot 20 = 1500$$
$$15 \cdot 80 = 1200$$
$$15 \cdot 28 = 420$$
$$16 \cdot 25 = 400$$
$$36 \cdot 20 = 720$$
$$25 \cdot 32 = 800$$
$$35 \cdot 24 = 840$$
$$16 \cdot 15 = 240$$
$$45 \cdot 12 = 540$$
$$18 \cdot 15 = 270$$
$$25 \cdot 64 = 1600$$
$$48 \cdot 15 = 720$$
$$55 \cdot 12 = 660$$
$$24 \cdot 50 = 1200$$
$$450 : 6 = 75$$
$$387 : 9 = 43$$
$$288 : 8 = 36$$
$$270 : 18 = 15$$
$$360 : 45 = 8$$
$$432 : 48 = 9$$
$$240 : 16 = 15$$
$$210 : 15 = 14$$
$$315 : 45 = 7$$
$$690 : 15 = 46$$
$$432 : 54 = 8$$
$$385 : 55 = 7$$
$$1000 : 20 = 50$$
$$1000 : 25 = 40$$
$$1000 : 50 = 20$$
Ответ
28) $$40\,500\ \text{мм}^2 < 4\ \text{дм}^2\ 50\ \text{см}^2,\ 40\,500\ \text{дм}^2 = 4\ \text{а}\ 5\ \text{м}^2,\ 40\,500\ \text{м}^2 < 40\ \text{га}\ 5\ \text{а},\ 40\,500\ \text{см}^2 = 4\ \text{м}^2\ 500\ \text{см}^2$$
29) $$24,\ 296,\ 43,\ 25,\ 215,\ 75,\ 900,\ 2500$$
