Tính nhẩm:
a. 1+1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9+9= ....?
b. 9-9+8-8+7-6+6-5+1-3+2+4+5+6-3-8=....?
1+2+3+4+5+6+7+8+9+1+2+3+4+5+6+7+8+9+1+2+3+4+5+6+7+8+9
1+2+3+4+5+6+7+8+9-1-2-3-4-5-6-7-8-9*2+1+2+3+4+5+6+7+8+9=
Tính nhẩm:
8 + 5 = .... 8 + 7 = ....
8 + 4 = .... 8 + 2 + 3 = ....
8 + 2 + 5 = .... 8 + 2 + 2 = ....
9 + 5 = .... 9 + 7 = ....
9 + 8 = .... 9 + 1 + 4 = ....
9 + 1 + 6 = .... 9 + 1 + 7 = ....
1+1+1+1+2+3+4+5+6+7+8+9+9+9+99999+99999+999999+999+888+0+0+99+8+7+7+6+6+5+4+4+4+5+6×7×6×4×5×77÷5÷46÷7=?
Ai nhanh mk tk
Tính nhẩm
9 + 1 + 8 = ….
5 + 5 + 4 = ….
8 + 2 + 2 = ….
9 + 1 + 6 = ….
7 + 3 + 2 = ….
6 + 4 + 1 = ….
Tính nhanh:
a)2+4+8+6+7+8+3+9+2+1;
b)3+2+4+9+7+1+8+6+3+5;
c)2+3+4+5+6+7+8+9+1+4.
1+2+3+4+5+6+7+8+9+1+2+3+4+5+6+7+8+9
1+1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9+9