Tính\(\frac{2^{18}.3^{17}-2^{17}.3^{16}}{6^{16}.2-2^{18}.3^{15}}\)
Tính nhẩm:
a)
15 − 6=..... 15 − 7=.....
15 − 8=..... 15 − 9=.....
16 − 7=..... 16 − 8=.....
16 − 9=..... 17 − 8=.....
17 − 9=..... 18 − 9=.....
b)
18 − 8 − 1=..... 18 − 9=.....
15 − 5 − 2=..... 15 − 7=.....
16 − 6 − 3=..... 16 − 9=.....
Phương pháp giải:
Trừ nhẩm các số rồi điền kết quả vào chỗ trống.
Lời giải chi tiết:
a)
15 − 6 = 9 15 − 7 = 8
15 − 8 = 7 15 − 9 = 6
16 − 7 = 9 16 − 8 = 8
16 − 9 = 7 17 − 8 = 9
17 − 9 = 8 18 − 9 = 9
b)
18 − 8 − 1 = 9 18 − 9 = 9
15 − 5 − 2 = 8 15 − 7 = 8
16 − 6 − 3 = 7 16 − 9 = 7
15 - 6 = 9,
15 - 8 =7,
15 - 7 = 8,
15 - 9 = 6
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
Tính:\(\frac{\frac{1}{18}+\frac{2}{17}+\frac{3}{16}+...+\frac{18}{1}+18}{\frac{1}{18}+\frac{1}{17}+\frac{1}{16}+...+1}\)
tính
a) |-18| . 941 + 59 . 18
b) 81 : 33 + 16 : 23
c) 30 - [ 40 - ( 6 - 1)2]
d) 17 . 85 + 15 . 17 - 150
a) |-18| . 941 + 59 . 18
= 18 . 941 + 59 . 18
= ( 941 + 59 ) . 18
= 1000 . 18
= 18000
b) 81 : 33 + 16 : 23
= 81 : 27 + 16 : 8
= 3 + 2
= 5
c) 30 - [ 40 - ( 6 - 1)2]
= 30 - [ 40 - 52 ]
= 30 - [ 40 - 25 ]
= 30 - 15
= 15
d) 17 . 85 + 15 . 17 - 150
= ( 85 + 15 ) . 17 - 150
= 100 . 17 - 150
= 1700 - 150
= 1550
a, \(\left|-18\right|\cdot941+59\cdot18=18\cdot941+59\cdot18=18\cdot\left(941+59\right)=18\cdot1000=18000\)
b, \(81:3^3+16:2^3=81\cdot27+16\cdot8=2187+128=2315\)
c, \(30-\left[40-\left(6-1\right)^2\right]=30-\left[40-5^2\right]=30-\left[40-25\right]=30-15=15\)
d, \(17\cdot85+15\cdot17-150=17\cdot\left(85+15\right)-150=17\cdot100-150=1700-150=1550\)
A= 2/1*3 - 4/3*5 + 6/5*7 - ...-16/15*17+ 18/17*19
Tìm A
Bài 1 Tính nhanh
a) -3/7 + 5/13 + 3/7
b) -5/21+-2/21+8/24
c) -5/11+(-6/11+2)
d) (-1/32+1/2)+15/32
e)5/17+ -6/13 + 3/4 + 7/-13+12/17
f) 7/23+-18/18+-4/9+16/23+-5/8
g)1/3+-3/4+3/5+-1/36+1/15+-2/9
h)-1/2+1/3+-1/4+-2/8+4/18+4/9
a)\(-\dfrac{3}{7}+\dfrac{5}{13}+\dfrac{3}{7}\)
=\(\left(-\dfrac{3}{7}+\dfrac{3}{7}\right)+\dfrac{5}{13}\)
=\(0+\dfrac{5}{13}\)
=\(\dfrac{5}{13}\)
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
Tính nhanh
1×2×3×4×5×6×7×8×9×10×11×12×13×14×15×16×17×18×19×20
bài 1:
1/4 + 2/3 2/7 + 2/3 2/5 + 1/3 2/3 + 1/2 1/3 + 3/5 4/5 + 1/3
1/8 + 3/4 1/36 + 5/12 1/3 + 1/6 + 1/18.
bài 2:
15/16 - 3/16 17/18 - 5/6 3/4 - 4/9 1/2 - 2/5 5/6 - 3/10 3-1/3
4/5 - 1/10 5/2 - 1 5/8 - 2/5.