9 + 11 + 13 + 17
= (9 + 11) + (13 + 17)
= 20 + 30
= 50
9 + 11 + 13 + 17=??
= (9 + 11) + (13 + 17)
= 20 + 30
= 50
9 + 11 + 13 + 17
= ( 9 + 11 ) + ( 13 + 17 )
= 20 + 30
= 50
9 + 11 + 13 + 17
= (9 + 11) + (13 + 17)
= 20 + 30
= 50
9 + 11 + 13 + 17=??
= (9 + 11) + (13 + 17)
= 20 + 30
= 50
9 + 11 + 13 + 17
= ( 9 + 11 ) + ( 13 + 17 )
= 20 + 30
= 50
Bài 13: Dấu <, =, >
10 … 10 + 3
11 + 2…. 2 + 11
9 … 10 + 9
10 … 10 + 0
17 – 4 … 14 - 3
18 – 4 … 12
15 … 15 – 1
17 + 1… 17 + 2
12+ 5 … 16
16 … 19 - 3
15 – 4 … 10 + 1
19 – 3 … 11
1+3+5+7+9+11+13+15+17+19=
Đặt tính rồi tính:
13 - 3 14 - 2 10 + 6 19 - 9
11 - 1 17 - 7 16 - 6 10 + 9
Tính nhẩm:
15 - 5 = 11 - 1 = 16 - 3 =
12 - 2 = 18 - 8 = 14 - 4 =
13 - 2 = 17 - 4 = 19 - 9 =
(-10)+(-9)+(-8)+...+0+1+2+3+...+10+11+12+13+14+15+16+17+18+19+20
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20=
11+11= 15+15=
12+12= 16+16=
13+13= 17+17=
14+14= 18+18=
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20=bao nhiêu?
Tính:1-2+3-4+5-6+7-8+9-10+11-12+13-14+15-16+17-18+19-20+21