tính tổng :
-9+...+(-1)+0+1+...+49 nói cách tính đầy đủ nha
19/13 + 14/16 + 1/9 +4/6 +7/13 + 17/9 nhớ ghi cách tính đầy đủ nha
\(\left(\frac{19}{13}+\frac{7}{13}\right)+\left(\frac{1}{9}+\frac{17}{9}\right)+\frac{14}{16}\)
= \(\frac{16}{13}+\frac{18}{9}+\frac{14}{16}\)
= \(\frac{42}{13}+\frac{14}{16}\)
= \(\frac{427}{104}\)
=(19/13 + 7/13 ) + (14/6 +4/6 ) +(1/9 +17/9 )
=26/13 +18/6 +18/9
=2 +3 + 2
=7
Tính tổng
B=1-2+5-4+9-6+.....50+101
Giải chi tiết đầy đủ nha
B=1-2+5-4+9-6+...-50+101
B= (1+5+9+...+101)-(2+4+6+...+50)
B=1071-625
B=446
1. Tính giá trị của biểu thức:
10 000 - 986 : 34 x 11
2. Tính bằng cách thuận tiện nhất:
3/7 + 4/9 + 4/7 + 5/9
(Các bạn viết bài giải đầy đủ ra cho mình nha.)
1.
= 10 000 - 29 x 11
= 10 000 - 319
= 9681
2.
= ( 3/7 + 4/7 ) + ( 4/9 + 5/9 )
= 1 + 1
= 2
3:tính bằng hai cách
(1/4+1/7)x1/3
trình bầy đầy đủ nha
\(\left(\dfrac{1}{4}+\dfrac{1}{7}\right)\times\dfrac{1}{3}\\ =\left(\dfrac{7}{28}+\dfrac{4}{28}\right)\times\dfrac{1}{3}\\ =\dfrac{11}{28}\times\dfrac{1}{3}\\ =\dfrac{11}{84}\)
C1:
\(\left(\dfrac{1}{4}+\dfrac{1}{7}\right)\times\dfrac{1}{3}\\ =\left(\dfrac{7}{28}+\dfrac{4}{28}\right)\times\dfrac{1}{3}\\ =\dfrac{11}{28}\times\dfrac{1}{3}\\ =\dfrac{11}{84}\)
C2:
\(\left(\dfrac{1}{4}+\dfrac{1}{7}\right)\times\dfrac{1}{3}\\ =\dfrac{1}{4}\times\dfrac{1}{3}+\dfrac{1}{7}\times\dfrac{1}{3}\\ =\dfrac{1}{12}+\dfrac{1}{21}\\ =\dfrac{7}{84}+\dfrac{4}{84}\\ =\dfrac{11}{84}\)
(1/4 + 1/7) x 1/3
= 11/28 x 1/3
= 11/84
(1/4 + 1/7) x 1/3
= 1/4 x 1/3 + 1/7 x 1/3
= 1/12 + 1/21
= 11/84
1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/40 nhớ ghi cách tính đầy đủ nha
=(1-1/2) + (1/2 - 1/3 ) + (1/3 - 1/4 ) + (1/4 - 1/5 ) + (1/5 - 1/6 ) + (1/6 - 1/7 )
=1-1/7
=6/7
Tính tổng
1+2-3-4-5+6+7+8-9-10-11....-63-64-65+66+67+68
Giải chi tiết đầy đủ nha
Câu 1: Nói về cách tiết kiệm năng lượng
Nói = tiếng anh nha
Ai nhanh + ngắn + gọn + đầy đủ ý
Đầy đủ các điều kiện trên thì được tick 3 cái nha
Mai mk thi rồi. Giúp mk với
Nowadays, energy is very important for our life, so we should use it more efficiently. We should use motorbikes and cars less to avoid increasing the tax on petrol. We should use low energy light bulbs, remember to turn off the light when you leave or go to bed to reduce our electric bills. We also should use public transport when you travel.
Nowadays, energy is necessary for our life. There are many kind of energy : ocean energy, electric energy, solar energy, wind energy... But energy also limit , so we must save energy. We can make some following ways.
To save petrol energy, we should:
+ Limit travel by car, motorbike, train...
You can using bicycles or walk.This not only help you save energy but also avoid traffic jams and can save your money any more.
- To save electricity energy, we should:
+ Turn off the light , the fans, the air-conditioner, you should close it after using.Avoid ironning close at peak hours...
+ When buying somethings, we should choose devices with costly a low electricity.
There are many ways to save water:
+ Turn off the faucet after using it
+ Don't let children play with water, if you let chidren play with water , this ill a lot of water.
- In the kitchen we should save gas energy by many ways:
+ turn off gas after cooking
+ don't use gas too much
+ when the food ripe, we should turn off gas immidiately to save gas.
- saving energy is our duty.
If you follow ways above, you can not only save energy but also save money very much and protect the environment.
Please make your dream come true!!
Hihi!!! ^ ^
tính:
a).2/5+1/2+7/10
b).4/9+11/8-5/6
c).9/20-8/15x5/12
d).2/3:4/5:7/12
làm đầy đủ phép tính+ cách tính đầy đủ tick
a) 2/5 + 1/2 + 7/10
= 4/10 + 5/10 + 7/10
= 9/10 + 7/10
= 16/10 = 8/5
b) 4/9 + 11/8 - 5/6
= 32/72 + 99/72 - 60/72
= 191/72
c) 9/20 - 8/15 x 5/12
= 9/20 - 2/9
= 41/180
d) 2/3 : 4/5 : 7/12
= 5/6 : 7/12
= 10/7
a,2/5+1/2+7/10
=4/10+5/10+7/10
=16/10
=8/5
b,4/9+11/8-5/6
=32/72+99/72-5/6
=131/72-5/6
=131/72-60/72
=71/72
c,9/20-8/15x5/12
=9/20-2/9
=41/180
d,2/3:4/5:7/12
=2/5x5/4x12/7
=6/7
Tính nhanh:
49 . 18 + 83 . 49 - 49
Ghi đầy đủ cách làm!
= 49 . ( 18 + 83 - 1 )
= 49 * 100
= 4900