Question

 Tính nhẩm: 

a, 2 x 3

6 x 2

10 x 2

1 x 2

b, 5 x 7

9 x 5

5 x 8

1 x 5

Answer 1

\(a,2\times3=6\)

\(6\times2=12\)

\(10\times2=20\)

\(1\times2=2\)

\(b,5\times7=35\)

\(9\times5=45\)

\(5\times8=40\)

\(1\times5=5\)