Tính giá trị biểu thức: a, 1 3/4 + 1/4 : 4/5 b, 2 2/3 x 1 1/4 - 1/6 c, 2 4/7 + 2 1/9 + 3/7 - 1/9 d, 6 1/15 + 5 7/17 + 2 14/15 + 3 10/17 e, 278 x 168 -68/100 + 168 x 277 h, 254 x 399 - 145/254 + 399 x 253 i, (35+36+37+38+...........+115) x (34 x 2 - 68)

$\text{a,}$ `1 3/4+1/4÷4/5`

` = 7/4+1/4×5/4`

` = 28/16+5/16`

` = 33/16`

$\text{b,}$ `2 2/3 × 1 1/4 -1/6`

` = 8/3×5/4-1/6`

` = 10/3 -1/6`

` = 20/6 - 1/6`

` = 19/6`

$\text{c,}$ `2 4/7+2 1/9+3/7-1/9`

` = (2 4/7 + 3/7) + (2 /19 -1/9)`

` = 3 + 2`

` = 5`

$\text{d,}$ `6 1/15 + 5 7/17 + 2 14/15 + 3 10/17`

` = (6 1/15 +2 14/15)+(5 7/17 +3 10/17)`

` = 9+9`

` =18`

$\text{e,}$ ` (278 × 168 -68)/(100 + 168 × 277)`

` = [(277+1) × 168 - 68]/(100 + 168 × 277)`

` = (277 × 168 + 168 - 68)/(100 + 168 × 277)`

` = (277 × 168 + 100)/(100 + 168 × 277)`

` = 1`

$\text{h,}$ `(254 × 399 - 145)/(254 + 399 × 253)`

` = [(253+1)×399-145]/(254+399×253`

` = (253×399+399-145)/(254+399×253)`

` = (253×399+254)/(254+399×253)`

` = 1`

$\text{i,}$ `(35+36+37+38+........+115)×(34×2-68)`

` = (35+36+37+38+........+115)×(68-68)`

` = (35+36+37+38+........+115)×0`

` =0`

Bạn có thể tham khảo!

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