1. Simplification ratio (1) 187cm: 17m (2) 0.25kg: 1g (3) 2 / 5 to 1 / 4 (4) 1.25 to 4.5 2 2. Calculate the ratio (1) 1 / 4: 1 / 5 (2) 18:3 (3) 0.0.001 (4) 0.4KG: 1.2m 3. Calculate the unknown x (1) 3: x = 9:18 (2) 25th x = 0.8 of 125 (3) 3 / 5 x-35% x = 1.25 (4) 25% x + 3 / 2 = 7.5 (5) 3x-120% = 9 / 20 (6) x-20% x = 8 / 5

1. Simplification ratio (1) 187cm: 17m (2) 0.25kg: 1g (3) 2 / 5 to 1 / 4 (4) 1.25 to 4.5 2 2. Calculate the ratio (1) 1 / 4: 1 / 5 (2) 18:3 (3) 0.0.001 (4) 0.4KG: 1.2m 3. Calculate the unknown x (1) 3: x = 9:18 (2) 25th x = 0.8 of 125 (3) 3 / 5 x-35% x = 1.25 (4) 25% x + 3 / 2 = 7.5 (5) 3x-120% = 9 / 20 (6) x-20% x = 8 / 5

1 (1) 187cm: 17m = 187cm: 1700cm = 11:100
(2) 0.25kg: 1g = 250g: 1g = 250:1
（3）2/5:1/4=（2/5×20）：(1/4×20)8:5
(4)1.25:4.5=(1.25×100):(4.5×100)=125:450=5:18
2(1)1/4:1/5=(1/4×20):(1/5×20)=5:4=5/4
(2)18:3=(18÷3):(3÷3)=6:1=6
(3) 0.5: 0.001 = 0.5: 0.6 = 5:6 = 5 / 6
(4) Units are not consistent, can not do
3（1）3：x=9:18
9x=3×18 x=6
(2)x/25=0.8/125 125x=25×0.8 x=20÷125 x=4/25
(3)3/5*x-35%x=1.25 0.6x-0.35x=1.25 0.25x=1.25 x=5
(4)25%x+3.5=7.5 25%=7.5-3.5 25%x=4 x= 16
(5)3x-1.2= 0.45 3x=0.45+1.2 x=0.55
(6)x-0.2x=1.6 0.8x=1.6 x=2