Предмет: Математика, автор: Anka2708

4 класс. Помогите, пожалуйста.

Приложения:

Wowagame29: На калькулятори сделай потом напиши
Anka2708: Здесь дело не в калькуляторе, а в поиске наиболее удобного способа решения, задание прочитай.
iramazurk: Ну не 40 же примеров делать! Это очень много
Anka2708: Спасибо, помощь уже не нужна, сами сжелали.
Anka2708: Сделали.
Wowagame29: Я какой в 6-ом класе

Ответы

Автор ответа: evvoronina1
1
1) 88 + 384 + 142 + 466 =
= 88 + 142 + 384 + 466 =
= 230 + 850 = 1080

2) 95 • 92 = 95 • (2 + 90) =
= 95 • 2 + 95 • 90 =
= 190 + (90 +5) • 90 =
= 190 + 90 • 90 + 90 • 5 =
= 190 + 8100 + 450 = 8740

3) 81 • 37 = 80 • 37 + 1•37 =
= 2960 + 37 = 2997

4) 135 : 5 = (100 + 35) : 5 =
= 100:5 + 35:3 = 20 + 7 = 27

5) 39 - 152 - 148 = 39 - (152 + 148) =
= 39 - 300 = -261

6) 35 • 18 = 35 • (2•9) =
= 35 • 2 • 9 = 70 • 9 = 630

7) 31³ = (30+1)³ =
= (30 + 1) • (30 + 1) • (30 + 1) =
= (30 • 30 + 30•1 + 30•1 + 1) • (30 + 1) =
= (900 + 60 + 1) • (30 + 1) =
= 900•30 + 60•30 + 1•30 + 900 + 60 + 1=
= 27000 + 1800 + 30 + 900 + 60 + 1 =
= 28800 + 900 + 91 =
29700 + 91 = 29791

8) 3284 - 129 - 184 + 279 =
= 3284 - 184 + 279 - 129 =
= 3100 + 150 = 325

9) 21 • 37 = (20 + 1) • 37 =
= 20 • 37 + 1•37 = 740 + 37 = 777

10) (125 - 6) • 8 = 125 • 8 - 6•8 =
= 1000 - 48 = 952

11) 52 • 48 = (50 + 2) • 48 =
= 50 • 48 + 2 • 48 =
= 2400 + 96 = 2496

12) 37 • 50 = 37 • (100:2) = 37 • 100 : 2 =
= 3700 : 2 = 1850

13) 84 • 9 = 84 • (10 - 1) =
= 84 • 10 - 84•1 = 840 - 84 = 756

14) 213 + (134 + 37) = 213 + 37 + 134 =
= 250 + 134 = 384

15) 76 • 25 = 76 • (100:4) =
= 76:4 • 100 = 19 • 100 = 1900

16) 17 • 18 = (10 + 7) • 18 =
= 10 • 18 + 7 • 18 = 180 + 126 = 306

17) (658 - 244) - (208 - 394) =
= 658 - 244 - 208 + 394 =
= (658 - 208) + (394 - 244) =
= 450 + 150 = 600

18) 72 • 125 = 72 • (1000:8) =
= 72:8 • 1000 = 9•1000 = 9000

19) 75² = (70 + 5)² =
= (70 + 5) • (70 + 5) =
= 70 • 70 + 70•5 + 5•70 + 5•5) =
= 4900 + 350 + 350 + 25 =
= 4900 + 700 + 25 = 5625

20) 897 - (112 + 547) =
= 897 - 112 - 547 =
= 897 - 547 - 112 =
= 350 - 112 = 238

21) 867 : 17 = (850 + 17) : 17 =
= 850 : 17 + 17 : 17 = 51 + 1 = 51

22) 52² = (50 + 2)² =
= (50 + 2) • (50 + 2) =
= 50 • 50 + 2•50 + 2•50 + 2•2 =
= 2500 + 100 + 100 + 4 =
= 2500 + 200 + 4 = 2704

23) 215 + 84 - 184 = 215 + (84 - 184) =
= 215 - 100 = 115

24) 325 : 25 = 325 • 4 : 100 =
= 1300 : 100 = 13

25) 295 • 12 = 295 • (10 + 2) =
= 295 • 10 + 295 • 2 =
= 2950 + 590 = 3540

26) 37 • 15 = 37 • (10 + 5) =
= 37 • 10 + 37 • 5 =
= 370 + 185 = 555

27) (761 + 281) + 339 =
= 761 + 339 + 281 =
= 1100 + 281 = 1381

28) 124 • 5 = (100 +20 + 4) • 5 =
= 100 • 5 + 20 • 5 + 4•5 =
= 500 + 100 + 20 = 620

29) 114 • 25 = 114 • 50 : 2=
= 114 : 2 • 50 = 57 • 50 =
= 57 • 100 : 2 = 5700 : 2 = 2850

30) 37 • 38 = 37 • (40 - 2) =
= 37 • 40 - 37 • 2 = 1480 - 74 = 1406

31) 25 • 2 • 7 • 4 • 8 • 5 =
= (25•4) • (2•5•8) • 7 =
= 100 • 80 • 7 = 100 • 560 = 56000

32) 112 : 14 = 112 : (2•7) = (112 : 2) : 7 =
= 56 : 7 = 8

33) 243 - (180 - 157) =
= 243 - 180 + 157 =
= 243 + 157 - 180 =
= 400 - 180 = 220

34) 589 + 397 =
590 - 1 + 400 - 3 = 990 - 4 = 986

35) 63 • 67 = (60 + 3) • (70 - 3) =
= 60•70 + 3•70 - 3•60 - 3•3 =
= 4200 + 210 - 180 - 9 =
= 4200 + 30 - 9 =
= 4200 + 21 = 4221

36) 16 • 125 • 5 • 3 =
= (8•2) • 125 • 5 • 3 =
= 8• 125 • 2•5 • 3 =
= 1000 • 10 • 3 = 10000 • 3 = 30000

37) (429 + 785) - (129 + 235) =
= 429 + 785 - 129 - 235 =
= 429 - 129 + 785 - 235 =
= 300 + 550 = 850

38) 84 • 24 = (80 + 4) • 24 =
= 80 • 24 + 4 • 24 =
= 1920 + 96 = 2016

39) 193 + 209 + 203 + 198 + 216 =
= 190+3 + 200+9 + 200+3 + 190+8 +210+6=
= 190 + 400 + 400 + 3+9+3+8+6 =
= 190 + 800 + 29 = 990 + 29 = 1019

40) (16 • 14) • (25 • 25) =
= (4•4) • 14 • 25 • 25 =
= 4•25 • 4•25 • 14 =
= 100 • 100 • 14 =
= 10000 • 14 = 140000



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