10+10=20
20+20=40
30+30=60
40+40=80
tk mk
10 + 10 = 20
20 + 20 = 40
30 + 30 = 60
40 + 40 = 80
10 + 10 = 20
20 + 20 = 40
30 + 30 = 60
40 + 40 = 80
10 + 10 = 20
20 + 20 = 40
30 + 30 = 60
40 + 40 = 80
10 + 10 = 20
20 + 20= 40
30 + 30= 60
40+40 =80
Chúc bn hok giỏi$$$$
10+10=20 / 20+20=40 / 30+30=60 / 40+40=80
Bài 1: Tính
a, 10 + 10 =20
b, 20 + 20 = 40
c, 30 + 30 = 60
d, 40 + 40 = 80
10+10=20
20+20=40
30+30=60
40+40=80