Question

Số?

Answer 1

Answer 2

a, 1 + 2 = 3

2 + 2 = 4

b, 1 + 1 = 2

3 +1 =4

2 +1 =3 

Answer 3

a)

`1+2=3`

`2+2=4`

b)

`1+1=2`

`3+1=4`

`2+1=3`

Answer 4

b) 1+1=2

    3+1=4

    2+1=3

Answer 5