1. Write two ratios that are two fifths and make up the proportion. 2. Make up four proportions with four numbers: 4, 10, 16 and 40 Write four ratios according to 4.5 × 1.6 = 9 × 0.8

1. Write two ratios that are two fifths and make up the proportion. 2. Make up four proportions with four numbers: 4, 10, 16 and 40 Write four ratios according to 4.5 × 1.6 = 9 × 0.8

1,2:5=6:15=2/5
2,4:16=10:40,4:10=16:40,40:16=10:4,40:10=16:4