Tính bằng cách thuận tiện nhất.

Hướng dẫn giải:

a) 72 600 – 28 900 + 32 150 + 8 300 = 72 600 + 8 300 – 28 900 + 32 150

                                                            = 80 900 – 28 900 + 32 150

                                                            = 52 000 + 32 150

                                                            = 84 150

b) 27 500 + 8 080 + 11 020 + 2 500 = (27 500 + 2 500) + (8 080 + 11 020)

                                                         = 30 000 + 19 100

                                                          = 49 100