1+2+3+4+5+6+7+8+9+10+11+12=78 nha bạn
1+2+3+4+5+6+7+8+9+10+11+12
=(12-1+1).(12+1)
=12.13
=156
Vay 1+2+3+4+5+6+7+8+9+10+11+12=156
1+2+3+4+5+6+7+8+9+10+11+12
= (1+9)+(2+8)+(3+7)+(4+6)+10+(5+11+12)
= 10+10+10+10+10+28
= 10 . 5 + 28
= 50+28=78
1+2+3+4+5+6+7+8+9+10+11+12=78 nha bạn
1+2+3+4+5+6+7+8+9+10+11+12
=(12-1+1).(12+1)
=12.13
=156
Vay 1+2+3+4+5+6+7+8+9+10+11+12=156
1+2+3+4+5+6+7+8+9+10+11+12
= (1+9)+(2+8)+(3+7)+(4+6)+10+(5+11+12)
= 10+10+10+10+10+28
= 10 . 5 + 28
= 50+28=78
1+2+3+4+5+6+7+8+9+10+11+12+13-1-2-3-4-5-6-7-8-9-10-11-12
tính nhanh
Bài 3: Tính
1 + 5 =
2 + 3 =
3 + 6 =
4 + 5 =
5 + 1 =
6 + 2 =
7 + 1 =
8 + 1 =
9 + 0 =
10 + 2=
11 + 2 =
1 + 3 =
2 + 6 =
3 + 7 =
4 + 2 =
5 + 2 =
6 + 3 =
7 + 3 =
8 + 2 =
9 + 1 =
10 + 0 =
11 + 3 =
1 + 4 =
2 + 8 =
3 + 2 =
4 + 1 =
5 + 4 =
6 + 4 =
7 + 2 =
8 + 0 =
9 + 2 =
10 + 6 =
11 + 6 =
Bài 4: Tính
6 - 2 =
3 - 1 =
4 - 2 =
5 - 2 =
8 - 5 =
10 - 6 =
4 - 3 =
3 - 3 =
5 - 1 =
2 - 2 =
3 - 1 =
4 - 1 =
2 - 1 =
4 - 3 =
5 - 0 =
9 - 4 =
8 - 6 =
7 - 3 =
8 - 4 =
7 - 6 =
9 - 5 =
7 - 7=
5 - 3 =
5 - 3=
6 - 3 =
7 - 3 =
7 - 6 =
6 - 5 =
9 - 7 =
9 - 3 =
8 - 8 =
8 - 0 =
5 - 3 =
Bài 5: Tính
6 - 2 =
5 + 2 =
9 - 5 =
2 + 0 =
8 + 2 =
4 - 4 =
7 - 3 =
3 + 6 =
7 + 2 =
9 - 5 =
3 + 6 =
1 + 5 =
7 - 6 =
7 + 1 =
3 + 5 =
2 - 1 =
6 + 3 =
5 + 2 =
9 - 4 =
6 + 4 =
4 + 2 =
6 + 1=
7 - 7=
4 + 3 =
7 + 3 =
5 - 2 =
6 - 5 =
8 - 6 =
6 - 4 =
7 - 3 =
10 + 0 =
5 +4 =
8 - 2 =
1+2+3+4+5+6+7+8+9+10+11+12=?
1+2+3+4+5+6+7+8+9+10+11+12=
1+2+3+4+5+6+7+8+9+10+11+12+.....+99
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15
Các bạn giúp mình trả lời câu hỏi này nha
1+2+3+4+5+6+7+8+9/1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+.....+366-102645/8.25 = ????????
1+2+3+4+5+6+7+8+9+10+11+12+13+..................................................................................................670+671-789
1+2+3+4+5+6+7+8+9+10 + 11 +12+13+14+15+16 = ?