Đáp án + Giải thích các bước giải:

`1)` `28 + 51 + 172.`

`= (28 + 172) + 51.`

`= 200 + 51.`

`= 251.`

`2)` `327 + 515 + 673.`

`= (327 + 673) + 515.`

`= 1000 + 515.`

`= 1515.`

`3)` `452 + 395 + 548 + 605.`

`= (452 + 548) + (395 + 605).`

`= 1000 + 1000.`

`= 2000.`

`4)` `5 \times 19 \times 4 \times 2 \times 25.`

`= (5 \times 2) \times (4 \times 25) \times 19.`

`= 10 \times 100 \times 19.`

`= 1000 \times 19.`

`= 19000.`

`5)` `8 \times 12 \times 125 \times 5.`

`= (8 \times 125) \times (12 \times 5).`

`= 1000 \times 60.`

`= 60000.`

`6)` `8 \times 2 \times 15 \times 125 \times 50.`

`= (8 \times 125) \times (2 \times 50) \times 15.`

`= 1000 \times 100 \times 15.`

`= 100000 \times 15.`

`= 1500000.`

`7)` `5 \times 125 \times 2 \times 4.`

`= (125 \times 4) \times (5 \times 2).`

`= 500 \times 10.`

`= 5000.`

`8)` `25 \times 50 \times 4 \times 20.`

`= (25 \times 4) \times (50 \times 20).`

`= 100 \times 1000.`

`= 100000.`

`9)` `176 + 483 + 24.`

`= (176 + 24) + 483.`

`= 200 + 483.`

`= 683.`

1) 28 + 51 + 172

= (28 + 172) + 51

= 200 + 51

= 251

2) 327 + 515 + 673

= (327 + 673) + 515

= 1000 + 515

= 1515

3) 452 + 393 + 548 + 605

= (452 + 548) + (393 + 605)

= 1000 + 998

= 1998

4) 5.19.4.2.25

= (5.2).(4.25).19

= 10.100.19

= 19000

5) 8.12.125.5

= (8.125).(12.5)

= 1000.60

= 60000

6) 8.2.15.125.50

= (8.125).(2.50).15

= 1000.100.15

= 1500000

7) 5.125.2.4

= (2.4.125).5

= 1000.5

= 5000

8) 25.50.4.20

= (25.4).(50.20)

= 100.1000

= 100000

9) 176 + 483 + 24

= (176 + 24) + 483

= 200 + 483

= 683