Ta có: 2 - 2 x 7
=> 2 x 7 = 14
Ta lấy: - 14 + 2 = - 12
Ta có: 2 - 2 x 7
=> 2 x 7 = 14
Ta lấy: - 14 + 2 = - 12
2 + 2 + 2 + 2 +2 = ?
1 x 3 + 3 x 5 + 5 x 7 + 7 x 9 + 9 x 11 = ?
1 x 2 = ?
1 x 2 x 3 = ?
1 x 2 x 3 x 4 = ?
1 x 2 x 3 x 4 x 5 = ?
1 x 2 x 3 x 4 x 5 x 6 = ?
1 x 2 x 3 x 4 x 5 x 6 x 7 = ?
1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 = ?
1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 = ?
1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 = ?
a.X x 5,2 : 4,5 = 10,5
b.5/7 x X + 2/7 x X = 2/3
Tính nhẩm :
2 x 3 = ... 2 x 2 = ...
2 x 5 = ... 2 x 4 = ...
2 x 7 = ... 2 x 6 = ...
2 x 8 = ... 2 x 1 = ...
2 x 9 = ... 2 x 10 = ...
7 x 7 x 10 x 2 =
2 x 3 + 2 x 7 =....
2x2−7x+10√=x+x2−12x+20√(2)
2 x 3 x 4 x5 x 6 x 7 x 8 x 0 + 2 = ??
2 x 1 =
2 x 2 =
2 x 3 =
2 x 4 =
2 x 5 =
2 x 6 =
2 x 7 =
2 x 8 =
2 x 9 =
2 x 10 =