比一比,看谁算得快又对。3+1= 2+3= 4+1=1+0= 5–2= 4–4=0+5= 1–0= 2+0=3+0= 4–2= 0+0=5–4= 5–3= 4–0=0–0= 5–1= 3–2=
308×5=
()-()=()
()+()=()
=