3.8 1.9
3.2 1.6 3.6 1.8 (3.8) (1.9) 3.9 1.95
①3.2+0.4=3.6+0.2=3.8+0.1=3.9
②3.2÷2=1.6 3.6÷2=1.8 3.8÷2=1.9 3.9÷2=1.95