4000:3000+4001:2999+4002:2998+...+6000:1000
Tính nhẩm:
a) 3000 + 5000 = ..........
5000 + 5000 = ..........
4000 + 4000 = ..........
7000 + 2000 = ..........
6000 + 1000 = ..........
2000 + 8000 = ..........
b) 2000 + 700 = ..........
100 + 1000 = ..........
6000 + 600 = ..........
8000 + 500 = ..........
5000 + 300 = ..........
400 + 6000 = ..........
a) 3000 + 5000 = 8000
5000 + 5000 = 10 000
4000 + 4000 = 8000
7000 + 2000 = 9000
6000 + 1000 = 7000
2000 + 8000 = 10 000
b) 2000 + 700 = 2700
100 + 1000 = 1100
6000 + 600 = 6600
8000 + 500 = 8500
5000 + 300 = 5300
400 + 6000 = 6400
a) 3000+5000=8000
5000+5000=10000
4000+4000=8000
7000+2000=9000
6000+1000=7000
2000+8000=10000
b) 2000+700=2700
100+1000=1100
6000+600=6600
8000+500=8500
5000+300=5300
400+6000=6400
a) 3000 + 5000 = 8000
5000 + 5000 = 10000
4000 + 4000 =8000
7000 + 2000 = 9000
6000 + 1000 = 7000
2000 + 8000 = 10000
b) 2000 + 700 = 9000
100 + 1000 = 1100
6000 + 600 =12000
8000 + 500 = 13000
5000 + 300 = 5300
400 + 6000 = 6400
tinh nhanh (tong day so ) :
1999 - 2000 + 2999 - 3000 + 3999 - 4000 + 4999 - 5000 + 5999 - 1000
1999 - 2000 + 2999 - 3000 + 3999 - 4000 + 4999 - 5000 + 5999 - 1000
=(1999-2000)+(2999-3000)+(3999-4000)+(4999-5000)+(5999-1000)
=1+(-1)+(-1)+(-1)+4999
=1x4+4999
=4+4999
=4999-4
=4995
tk nha
cac ban chinh bay cach giai ra nhe . day la tinh nhanh ma .
Tính:1/2+1/3+...+1/3000 / 2999/1+2998/2+...+1/2999
Xét mẫu :
\(\frac{2999}{1}+\frac{2998}{2}+.....+\frac{1}{2999}\)
=\(\left(1+\frac{2998}{2}\right)+\left(1+\frac{2997}{3}\right)+....+\left(1+\frac{1}{2999}\right)+1\)
=\(\frac{3000}{2}+\frac{3000}{3}+.....+\frac{3000}{2999}+\frac{3000}{3000}\)
=\(3000\left(\frac{1}{2}+\frac{1}{3}+....+\frac{1}{3000}\right)\)
Thay vào ta có:
\(\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{3000}}{3000\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+....+\frac{1}{3000}\right)}\)
=\(\frac{1}{3000}\)
Tính nhanh: 1999-2000+2999-3000+3999-4000+4999-5000+5999-1000
1999-2000+2999-3000+3999-4000+4999-5000+5999-1000
=(1999-2000)+(2999-3000)+(3999-4000)+(4999-5000)+(5999-1000)
=-1+(-1)+(-1)+(-1)+4999
=-1x4+4999
=-4+4999
=4999-4
=4995
1999 - 2000 + 2999 - 3000 + 3999-4000+ 4999-5000+5999-1000
= ( 2000-1999) + ( 3000-2999) + ( 4000-3999) + ( 5999-5000) -1000
= 1 + 1 + 1 + 1 -1000
=4 -1000
= 1000-4
=996
1999-2000+2999-3000+3999-4000+4999-5000+5999-1000=4995
k cho mk nha năn nỉ đó
1000+2000+3000+4000+5000+6000
nhớ kết bn với mình nha
1000 + 2000 + 3000 + 4000 + 5000 + 6000
= ( 1000 + 6000 ) + ( 2000 + 5000 ) + ( 3000 + 4000 )
= 7000 + 7000 + 7000
= 21000
Tính nhanh :
1000 + 2000 + 3000 + 4000 + 5000 + 6000 + 7000 + 8000 + 9000 + 5000
1000 +9000 +2000+8000+3000+7000+4000+6000+5000+5000
= 10000+10000+10000+10000+10000
=50000
k nhá !
Cho N = 30 /1 + 30 / 2 + 30 / 3 +.....+ 30 / 3000 và M = 2999 / 1 + 2998 / 2 + 2997 / 3 + ...+ 1 / 2999
Tính N : M
Tính nhanh :
1000 + 3000 + 6000 + 9000 + 4000 + 5000 + 7000 + 5000
Ai k mình,mình k lại nha
1000+3000+6000+9000+4000+5000+7000+5000
= (1000+9000)+(3000+7000)+(6000+4000)+(5000+5000)
=10000+10000+10000+10000
=40000
t mk nha bn
(1000+5000)+(3000+7000)+(6000+4000)+9000
=6000+10000+10000+9000
=(10000+100000+(6000+9000)
=20000+15000
=35000
Tính nhẩm :
3000 + 6000 = ...... 4000 + 500 = ......
2000 + 5000 = ...... 6000 + 4000 = ......
3000 + 6000 = 9000 4000 + 500 = 4500
2000 + 5000 = 7000 6000 + 4000 = 10 000.