10 +10-10+10-20+100 =???
10 + 10 - 10 . 10 : 10 + 20 - 20 : ......... - 100 . 100 :100 + .......... 1000 - 1000 . 1000 : 1000 = ?
Ta có:
= 10-10.10:10
= 10 - 100 : 10
= 10 - 10
= 0
Vì các số có quá trình tương tự nên kết quả là : 10 + 0 + 0 + 0 + 0 +...+ 0 = 10
100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 nha
20 + 20 /10 +87 +88 +90 +10 *100 /10 * 800 / 1000 =
\(20+\frac{20}{10}+87+88+90+\frac{10\times100}{10}\times\frac{800}{1000}\)
\(=20+2+175+90+100+0,8\)
\(=22+265+100,8\)
\(=287+100,8\)
\(=387,8\)
20 . (10 + 10 ) + 320 .10 . 100 . 20
ai nhanh mik tích cho
20 . (10 + 10) + 320 . 10 . 20
= 20 . 20 + 64000
= 64400
Tính giá trị của biểu thức:
a) 90 – ( 30 – 20) = ..........................
= ..........................
90 – 30 – 20 = ..........................
= ..........................
b) 100 – (60 + 10) = ..........................
= ..........................
100 - 60 + 10 = ..........................
= ..........................
c) 135 – (30 + 5) = ..........................
= ..........................
135 – 30 – 5 = ..........................
= ..........................
d) 70 + (40 – 10) = ..........................
= ..........................
70 + 40 – 10 = ..........................
= ..........................
a) 90 – ( 30 – 20) = 90 – 10
= 80
90 – 30 – 20 = 60 - 20
= 40
b) 100 – (60 + 10) = 100 – 70
= 30
100 - 60 + 10 = 40 + 10
= 50
c) 135 – (30 + 5) = 135 – 35
= 100
135 – 30 – 5 = 105 – 5
= 100
d) 70 + (40 – 10) = 70 + 30
= 100
70 + 40 – 10 = 110 -10
= 100
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687 + ( 2 x 5 ) + 10 =
Mẫu
600 + ( 2 x 5 ) + 20 + 100 =
Thực hiện phép tính 2 x 5
2 x 5 = 2 + 2 + 2 + 2 + 2 = 10
2 x 5 = 10
600 + 10 + 20 + 100 = 730
`687 + (2 × 5) + 10`
`= 687 + 10 + 10`
`= 697 + 10`
`= 707`
tính
F= x14 - 10.x13 + 10.x12 - 10.x11 + ...+ 10.x2 + 10.x + 10 tại x = 9
G= x5-100.x^4 - 100.x^2 +100.x -9 tại x=99
H= x^6 -20.x^5 -20.x^4 - 20.x^3 -20.x^2 + 20.x + 3 tai x=21
C1 : lần trước mình giải
C2 : mình không chắc thử xem
thay x= 9 vao F ta có
F = 9^14 - 10 .9^13 + 10.9^12 - 10 .9^11 + ... +10.9^2 -10.9 + 10
= 9^14 - ( 9 + 1 ) . 9^13 + (9+1). 9^12+..+(9+1) .9^2 - (9+1)9 +10
= 9^14 - 9^14 - 9^13 + 9^13 + 9^12 -.....+9^3 + 9^2 - 9^2 - 9 + 10 = 1
Tương tự vói G , H
Bài 7: Chứng tỏ rằng:
1/2^2 + 1/3^2 + 1/4^2 + ...1/100^2 < 3/4
Bài 8: So sánh A= 20^10 + 1 / 20^10 - 1 và B= 20^10 - 1 / 20^10 - 3.
8:
\(A=\dfrac{20^{10}-1+2}{20^{10}-1}=1+\dfrac{2}{20^{10}-1}\)
\(B=\dfrac{20^{10}-3+2}{20^{10}-3}=1+\dfrac{2}{20^{10}-3}\)
mà 20^10-1>20^10-3
nên A<B
10*10=?
10*20=?
10*30=?
10*40=?
10*50=?
10*60=?
10*70=?
10*80=?
10*90=?
10*100=?
10*10=100
10*20=200
10*30=300
10*40=400
10*50=500
10*60=600
10*70=700
10*80=800
10*90=900
10*100=1000
10 * 10 = 100
10 * 20 = 200
10 * 30 = 300
10 * 40 = 400
10 * 50 = 500
10 * 60 = 600
10 * 70 =700
10 *80 = 800
10 * 90 = 900
10 * 100 = 1000
100:10+20+30-10