𝟭. $\\$ ` => ` $\dfrac{15/25}{+5}$ $\\$ ` => 15/25 + 125/25 ` $\\$ ` -> 5,6. ` $\\$ ------------------------------------------------ $\\$ ` => 3/2 - 4/8 ` $\\$ ` => 3/2 - 1/2 ` $\\$ ` => 3-1/2 ` $\\$ ` -> 1. ` $\\$ ------------------------------ $\\$ ` => ` $\dfrac{2/9}{×5}$ $\\$ ` => 2/9 × 5/1 ` $\\$ ` => 2/9 × 5/1 ` $\\$ ` => 2×5/9×1 ` $\\$ ` => ` $\dfrac{10/}{9×1}$ $\\$ ` -> 10/9. ` $\\$ ------------------------------- $\\$ ` => 6/7 ÷ 3/4 ` $\\$ ` => 6/7 × 4/3 ` $\\$ ` -> 8/7 ` $\\$ ------------------------------------------------------ $\\$ 𝟮. $\\$ 𝙖. $\\$ ` => 51/60 × 12/17 ÷ 3/10 ` $\\$ ` => 51/60 × 12/17 × 10/3 ` $\\$ ` -> 2. ` $\\$ ----------------------------------------------------- $\\$ 𝙗. $\\$ ` => 5/12 ÷ 7/4 - 25/18 ÷ 35/6 ` $\\$ ` => 5/21 - 25/18 ÷ 35/6 ` $\\$ ` => 5/21 - 5/21 ` $\\$ ` -> 0. ` $\\$ ------------------------------------------------------------ $\\$ 𝟯. $\\$ ` => 2/5 + 1/2 - 7/10 ` $\\$ ` => 2/5 + 1/2 - 7/10 ` $\\$ ` => 2×2/5×2 + 1×5/2×5 - 7/10 ` $\\$ ` => 4/10 + 5/10 - 7/10 ` $\\$ ` => ` $\dfrac{4+5-7}{10}$ $\\$ ` => 2/10. ` $\\$ ` -> 0,2. ` $\\$ -------------------------------------------------------------- $\\$ ` => 4/7 ÷ 8/11 ` $\\$ ` => 4/7 × 11/8 ` $\\$ ` -> 11/14. ` $\\$ ----------------------------------------- $\\$ $ #tolanhat01$

15/25+5=5.6

( mình lấy mẫu số là 8 lun)3/2-4/8=24/8-4/8=20/8

2/9×5=1(1)

6/7÷3/4=24/21(rút gọn cho 3)=8/7