50道加法结合律的算式

加法结合律是指：三个数相加，先把前两个数相加，或者先把后两个数相加，和不变。用字母表示为：(a+b)+c=a+(b+c)。

以下是50道应用加法结合律的算式示例：

1. (1+2) + 3 = 1 + (2+3)
2. (4+5) + 6 = 4 + (5+6)
3. (7+8) + 9 = 7 + (8+9)
4. (10+11) + 12 = 10 + (11+12)
5. (13+14) + 15 = 13 + (14+15)
6. (16+17) + 18 = 16 + (17+18)
7. (19+20) + 21 = 19 + (20+21)
8. (22+23) + 24 = 22 + (23+24)
9. (25+26) + 27 = 25 + (26+27)
10. (28+29) + 30 = 28 + (29+30)
11. (31+32) + 33 = 31 + (32+33)
12. (34+35) + 36 = 34 + (35+36)
13. (37+38) + 39 = 37 + (38+39)
14. (40+41) + 42 = 40 + (41+42)
15. (43+44) + 45 = 43 + (44+45)
16. (46+47) + 48 = 46 + (47+48)
17. (49+50) + 51 = 49 + (50+51)
18. (52+53) + 54 = 52 + (53+54)
19. (55+56) + 57 = 55 + (56+57)
20. (58+59) + 60 = 58 + (59+60)
21. (61+62) + 63 = 61 + (62+63)
22. (64+65) + 66 = 64 + (65+66)
23. (67+68) + 69 = 67 + (68+69)
24. (70+71) + 72 = 70 + (71+72)
25. (73+74) + 75 = 73 + (74+75)
26. (76+77) + 78 = 76 + (77+78)
27. (79+80) + 81 = 79 + (80+81)
28. (82+83) + 84 = 82 + (83+84)
29. (85+86) + 87 = 85 + (86+87)
30. (88+89) + 90 = 88 + (89+90)
31. (91+92) + 93 = 91 + (92+93)
32. (94+95) + 96 = 94 + (95+96)
33. (97+98) + 99 = 97 + (98+99)
34. (2+4) + 6 = 2 + (4+6)
35. (5+7) + 9 = 5 + (7+9)
36. (8+10) + 12 = 8 + (10+12)
37. (11+13) + 15 = 11 + (13+15)
38. (14+16) + 18 = 14 + (16+18)
39. (17+19) + 21 = 17 + (19+21)
40. (20+22) + 24 = 20 + (22+24)
41. (23+25) + 27 = 23 + (25+27)
42. (26+28) + 30 = 26 + (28+30)
43. (29+31) + 33 = 29 + (31+33)
44. (32+34) + 36 = 32 + (34+36)
45. (35+37) + 39 = 35 + (37+39)
46. (38+40) + 42 = 38 + (40+42)
47. (41+43) + 45 = 41 + (43+45)
48. (44+46) + 48 = 44 + (46+48)
49. (47+49) + 51 = 47 + (49+51)
50. (50+52) + 54 = 50 + (52+54)

这些算式都展示了加法结合律的应用，即改变加数的组合顺序，其和保持不变。