41 * 66+ 34 * 41 / 3+7+11+...+79
Tính hợp lý:A=41*66+34*41/3+7+11+...+79
\(a,A= 41 . 66 + 34 . 41/ 3+ 7+11+...+79 \)
tinh nhanh
a,A=100+98+96+...+2-97-95-...-1
b,B=1+2-3-4+5+6-7-8+9+10-11-12+...-229-330+301+302
c,C=41*66+34*41/3+7+11+...+79
d,D=1+2+3+...+200/6+8+10+...+34
e,E=1*5*6+2*10*12+20*24*4+9*45*54/1*3*5+2*6*10+4*12*20+9*27*45
Bai1 tính nhanh phép tính
a) 37581-9999
Bài2 tính nhanh
a) 36×28+36×82+64×69+64×41
b) A=41×66+34×41/3+7+11+...+79
c) 1×5×6+2×10×12+4×20×24+9×45×54/1×3×5+2×6×10+4×12×20+9×27×45
Bài 1 :
a) 37581 - 9999 = 37581 - 10000 - 1 = 27581 - 1 = 27580
k cho mình nha bạn !
a)37581-9999=37581-(9999+1-1)=37581-(10000+1)=37581-10000-1=27581+1=27582
ai giúp mình zới
tính bằng cách hợp lý
A= 44 x 66 + 34 x 41 phần 3+7+11+....+79
nhanh nhé
cái kia là phân số mình ko biết ghi nên viết vậy
Mik sửa lại đề một chút nha :
\(\frac{44.66+34.44}{3+7+11+...+79}\)
Ta có :
\(\frac{44.66+34.44}{3+7+11+...+79}\)
\(=\frac{44\left(66+34\right)}{820}\)
\(=\frac{4400}{820}\)
\(=\frac{220}{41}\)
Vậy \(A=\frac{220}{41}\)
Đặt B = 44 x 66 + 34 x 44
C = 3 + 7 + 11 + ... + 79
Ta có:
B = 44 x 66 + 34 x 44
= 44 x ( 66 + 34 )
= 44 x 100
= 4400
C = 3 + 7 + 11 + ... + 79
C = 79 + 75 + 71 + ... + 3
C = ( 3 + 79 ) + ( 7 + 75 ) + ( 11 + 71 ) + ... + ( 79 + 3 ) ( 10 cặp số )
C = 82 + 82 + 82 + ... + 82 ( 10 số 82 )
C = 10 x 82
C = 820
\(\Rightarrow A=\frac{4400}{820}=\frac{220}{41}\)
Mk có sửa đề chút nhé
bn ơi cái này là x hay nhân thế
2/15-2/65-4/39
32/13-(7/23+8/23)
(1/3+12/67+13/41) - (79/67 - 28/41)
38/45 - (8/45-17/51-3/11)
2/15-2/65-4/39=4/39-4/39=0
32/13-(7/23+8/23)=32/13-15/23=541/299
(1/3+12/67+13/41) - (79/67 - 28/41)=6836/8241-1363/2747=1/3
38/145 - (8/45-17/51-3/11)=38/145-(-212/495)=1982/2871
Tính nhanh
a) 31/23 - (7/32 + 8/23)
b) 38/45 - (8/45 - 17/51 - 3/11)
c)(1/3 + 12/67 + 13/41) - ( 79/67 - 28/41)
d) 1/5 + -1/6 + 1/7 + -1/8 + 1/9 + 1/8 + -1/7 + 1/6 + -1/5
Tính nhanh
a) 31/23 - (7/32 + 8/23)
b) 38/45 - (8/45 - 17/51 - 3/11)
c)(1/3 + 12/67 + 13/41) - ( 79/67 - 28/41)
d) 1/5 + -1/6 + 1/7 + -1/8 + 1/9 + 1/8 + -1/7 + 1/6 + -1/5
`a,`
`31/23-(7/32+8/23)`
`=31/23-7/32-8/23`
`=(31/23-8/23)-7/32`
`=1-7/32=25/32`
`b,`
`38/45-(8/45-17/51-3/11)`
`=38/45-8/45+17/51+3/11`
`= (38/45-8/45)+17/51+3/11`
`=2/3+17/51+3/11`
`=1+3/11=14/11`
`c,`
`(1/3+12/67+13/41)-(79/67-28/41)`
`= 1/3+12/67+13/41-79/67+28/41`
`= 1/3+(12/67-79/67)+(13/41+28/41)`
`= 1/3+(-1)+1=1/3+(-1+1)=1/3+0=1/3`
`d,`
`1/5+(-1/6)+1/7+(-1/8)+1/9+1/8+(-1/7)+1/6+(-1/5)`
`= (1/5+ -1/5)+(-1/6+1/6)+(1/7+ -1/7)+(-1/8 +1/8)+1/9`
`= 0+0+0+0+1/9=1/9 .`
Bỏ ngoặc rồi tính: 1. (56+47)-(56-53+40) 2. (34+59)-(34-41-100) 3. (109+34)-(109-66+10)
1.\(=56+47-56+53-40\)
\(=\left(56-56\right)+\left(47+53\right)-40\)
\(=0+100-40=60\)
2.\(34+59-34+41+100\)
\(=\left(34-34\right)+\left(59+41\right)+100\)
\(=0+100+100=200\)
3.\(=109+34-109+66-10\)
\(=\left(109-109\right)+\left(34+66\right)-10\)
\(=0+100-10=90\)