(18 . 1/2 . -14) . 1/3 . 1/2 . -12
1+1+2+2+3+3+4+4+5+5+6+6+10+10+12+12+14+14+16+16+18+18+20+20+7+7+8+8+9+9
GIUP MK VOI MK TICK CHO NGUOI NHANH NHAT
1+1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9+9=2+4+6+8+10+12+14+16+18
=(2+8)+(4+6)+10+(12+18)+(14+16)
=10+10+10+30+30
=30+30+30
=30x3
=90
tính : a) 2/3 *( 2/18+6/12-3/33 ) b) 6/14+4/25-5/10*3/16 c)5/25*(9/18+16/32-12/46) + 9/17 d)11/32:(14/18-16/27) + (2/3-5/15) e) ( 1/9+2/17)+3/6-(12/17-1/2) +5/9
1+1/1+2+1/1+2+3+...+1/1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19
Tính:
12 - 1 = 13 - 1 = 14 - 1 =
17 - 5 = 18 - 2 = 19 - 8 =
14 - 0 = 16 - 0 = 18 - 0 =
12 - 1 = 11 13 - 1 = 12 14 - 1 = 13
17 - 5 = 12 18 - 2 = 16 19 - 8 = 11
14 - 0 = 14 16 - 0 = 16 18 - 0 = 18
Tính nhẩm:
15 + 1 = 10 + 2 = 14 + 3 = 13 + 5 =
18 + 1 = 12 + 0 = 13 + 4 = 15 + 3 =
15 + 1 = 16 10 + 2 = 12 14 + 3 = 17 13 + 5 = 18
18 + 1 = 19 12 + 0 = 12 13 + 4 = 17 15 + 3 = 18
15+1=16 10+2=12 14+3=17 13+5=18 18+1=19 12+0=12 13+4=17 15+3=18
\(\dfrac{15}{12}+\dfrac{5}{13}-\dfrac{3}{12}-\dfrac{18}{13}-\dfrac{1}{3}\)
\(14.\dfrac{3}{2}+\dfrac{6}{5}:\left(\dfrac{-2}{5}\right)\)
\(\sqrt{\dfrac{1}{4}+\dfrac{2}{3}-\left(\dfrac{1}{3}\right)^2}\)
\(\dfrac{15}{12}+\dfrac{5}{13}-\dfrac{3}{12}-\dfrac{18}{13}-\dfrac{1}{3}\)
\(=\left(\dfrac{15}{12}-\dfrac{3}{12}\right)+\left(\dfrac{5}{13}-\dfrac{18}{13}\right)-\dfrac{1}{3}\)
\(=-1+1-\dfrac{1}{3}\)
\(=0-\dfrac{1}{3}\)
\(=\dfrac{-1}{3}\)
------------------------------------------
\(14.\dfrac{3}{2}+\dfrac{6}{5}:\left(-\dfrac{2}{5}\right)\)
\(=14.\dfrac{3}{2}+\dfrac{6}{5}.\dfrac{-5}{2}\)
\(=21+\dfrac{6}{5}.\dfrac{-5}{2}\)
\(=21+\left(-3\right)\)
\(=18\)
------------------------------------------------
\(\sqrt{\dfrac{1}{4}+\dfrac{2}{3}-\left(\dfrac{1}{3}\right)^2}\)
\(=\sqrt{\dfrac{1}{4}+\dfrac{2}{3}-\dfrac{1}{9}}\)
\(=\sqrt{\dfrac{3}{12}+\dfrac{8}{12}-\dfrac{1}{9}}\)
\(=\sqrt{\dfrac{11}{12}-\dfrac{1}{9}}\)
\(=\sqrt{\dfrac{99}{108}-\dfrac{12}{108}}\)
\(=\sqrt{\dfrac{29}{36}}\)
\(=\dfrac{\sqrt{29}}{6}\)
\(\dfrac{15}{12}+\dfrac{5}{13}-\dfrac{3}{12}-\dfrac{18}{13}-\dfrac{1}{3}\)
\(=\dfrac{5}{4}+\dfrac{5}{13}-\dfrac{1}{4}-\dfrac{18}{13}-\dfrac{1}{3}\)
\(=\left(\dfrac{5}{4}-\dfrac{1}{4}\right)+\left(\dfrac{5}{13}-\dfrac{18}{13}\right)-\dfrac{1}{3}\)
\(=1+\left(-1\right)-\dfrac{1}{3}=0-\dfrac{1}{3}=-\dfrac{1}{3}\)
1 + 2 + 3 + ... + 99 + 100
2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18
1 + 2 + 3 + 4 + ... + 200
1+2+3+...+99+100
=(1+100)x50
=101x50
=5050
2+4+6+8+10+...+18
=(2+18):2 x9
=90
1+2+3+4+...+200
=(1+200)x 100
=201 x100
=20100
1+2+3+...+99+100
=(1+100)x50
=101x50
=5050
2+4+6+8+10+...+18
=(2+18):2 x9
=90
1+2+3+4+...+200
=(1+200)x 100
=201 x100
=20100
1+2+3+...+99+100
=(1+100)x50
=101x50
=5050
2+4+6+8+10+...+18
=(2+18):2 x9
=90
1+2+3+4+...+200
=(1+200)x 100
=201 x100
=20100
1. Tính ( Phân số )
1) -5/24+16/27+0,75
2)-4/12+6/7+8/24
3)9/18+-7/12+-16/-32
4)5/-8+14/25+-6/10
2. Tìm x , biết :
1) 1/3 + 1/33 < x/210 < -4/-7 + 3/5 + -2/3 (x thuộc Z )
2) 5/3 + -14/3 < x < 1/5 +18/10 ( x thuộc Z )
Bài 1:
1: =-5/24+16/27+3/4
=-5/24+18/24+16/27
=13/24+16/27
=117/216+128/216=245/216
2: =-1/3+1/3+6/7=6/7
3: \(=\dfrac{1}{2}-\dfrac{7}{12}+\dfrac{1}{2}=1-\dfrac{7}{12}=\dfrac{5}{12}\)
4: \(=-\dfrac{5}{8}+\dfrac{14}{25}-\dfrac{6}{10}=\dfrac{-125+112-120}{200}=\dfrac{-133}{200}\)
7-(2x-1/3)^2=3
(2x+1/3)^2-3/8=1/8
12:[29-(x-2/3)^2]=3
(3x-1/2)^3+8/3=29/9-14/27
2(2x-1/3)^2+4/3=5/6+13/18
Tìm X
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
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