T: Children, please finish the arithmetic in P 44, OK?
    1) 7+5= 2) 6+12= 3) 36- 20 = 4) 23- 4=
Ps: Ok.
A few minutes later.

T: Now, let’s correct the answer. What is seven and five, Ben?

P1: Is it twelve?

T: That’s right. Next one. What is six and twelve, Janet?

P2: I think it’s eighteen.

T: Very great. What is thirty-six minus twenty, Sally?

P3: Sorry, I don’t know.

T: Never mind(没关系). Who can help her?

P4: Miss White, it’s sixteen.

T: Wonderful. And the last one: What is twenty-three minus four, Yongxian?

P5: Twenty-three minus four is nineteen.

T: Super. You’re all right.