24) 15 (4-7)- 15 (5-3)
25) 73(8-59) -59(8-73)
Tính hợp lý:
15 x (4-7) -15 x (5-3)
73 x (8-59)-59 x(8-73)
15 × (4 - 7) - 15 × (5 - 3)
= 15 × (-3) - 15 × 2
= 15 × (-3 - 2)
= -15 × 5
= -75
--------
73 × (8 - 59) - 59 × (8 - 73)
= 73 × 8 - 73 × 59 - 59 × 8 + 59 × 73
= 8 × (73 - 59) + 73 × (59 - 59)
= 8 × 14 + 73 × 0
= 8 × 14
= 112
15 x (4-7) - 15 x (5-3)
= 15 x (-3) - 15 x (-2)
= 15 x (-3 - (-2))
= 15 x (-1)
= -15
73 x (8-59) - 59 x (8-73)
= 73 x 8 - 59 x 73 - 59 x (-65)
= 73 x 8 - 59 x (73 - (-65))
= 73 x 8 - 59 x 8
= 8 x (73-59)
= 8 x 14
= 112
a) 15 × (4 - 7) - 15 × (5 - 3)
= 15 × (-3) - 15 × 2
= 15 × (-3 - 2)
= -15 × 5
= -75
b) 73 × (8 - 59) - 59 × (8 - 73)
= 73 × 8 - 73 × 59 - 59 × 8 + 59 × 73
= 8 × (73 - 59) + 73 × (59 - 59)
= 8 × 14 + 73 × 0
= 8 × 14
= 112
Tính hợp lí:
73.(8-59)-59.(8-73)159.(18-59)-59.(18-159)-145.(13-57)+57.(10-145)17.(15-16)+16.(17-20)-38.(25-4)+35.(-4+38)23.(145-17)-145.(23-6)199.(15-17)-199.(-17+5)-39.(5-99)+99.(10-39)
1.73.(8-59)-59.(8-73)
=73.8-73.59-59.8-59.73
=73.(59-59)-8.(73-59)
=73.0-8.14
=0-112
=-112
2.159.(18-59)-59.(18 - 159)
=159.18-59.159-59.18-59.159
=159.(59-59)-18.(159-59)
=159.0-18.100
=0-1800
=-1800
73(8-59)-15(5-3)
73.(8-59) -15.(5-3)
= 73 . (-51)-15.2
= [73.(-51) ] - (15.2)
= -3723 -30
=(-3753)
73.(8-59) -15.(5-3)
= 73 . (-51)-15.2
= [73.(-51) ] - (15.2)
= -3723 -30
= -3753
73(8-59)-15(5-3)
= 73.(-51)-15.2
= -3723-30
= -3753
1)thực hiện phép tinh ( hợp lí nếu có thể )
a) 73.(8-59) - 59.(8-73)
b)199.(15-17) - 199.( -17 + 5 )
a) \(73\left(8-59\right)-59\left(8-73\right)\)
\(=73.8-73.59-59.8+59.73\)
\(=8.\left(73-59\right)\)
\(=8.14=112\)
b) \(199\left(15-17\right)-199\left(-17+5\right)\)
\(=199.15-199.17+199.17-199.5\)
\(=199.\left(15-5\right)\)
\(=199.10=1990\)
a) 73.(8-59) - 59.(8-73)
= 73 . 8 - 73 . 59 - 59 . 8 + 59 . 73
= - 73 . 59 + 59 . 73 + 73 . 8 - 59 . 8
= 0 + 8 ( 73 - 59 )
= 8 . 14
= 112
b)199.(15-17) - 199.( -17 + 5 )
= 199 . 15 - 199 . 17 - 199 . (- 17 ) + ( - 199 ) . 5
= 199 . 15 - 19 . 17 + 199 . 17 + ( - 199 ) . 5
= 199 . 15 - 0 + 199 . ( - 5 )
= 199 . [ 15 - ( - 5 ) ]
= 199 . 10
= 1990
1) thực hiện phép tính ( hợp lý nếu có thể )
a) 199(15-17)-199(-17+5)
b) 73(8-59)-59(8-73)
a) \(199\left(15-17\right)-199\left(-17+5\right)\)
\(=199.15-199.17+199.17-199.5\)
\(=199.\left(15-5\right)\)
\(=199.10=1990\)
b) \(73\left(8-59\right)-59\left(8-73\right)\)
\(=73.8-73.59-59.8+59.73\)
\(=8\left(73-59\right)\)
\(=8.14=112\)
tinh 1 cach hop li; a, -39.(5-99)+99.(10-39) b,153.177-153.77 c, 199.(15-17)-99.(-17+5) d, 73.(18-59)-59.(8-73)
a: =-39*5+39*99+99*10-99*39
=-39*5+99*10
=990-195=795
b: =153(177-77)=15300
c: =199*15-199*17+99*17-99*5
=17(-100)+199*15-99*5
=790
d: =73*18-73*59-59*8+59*73
=73*18-59*8
=842
73.(8-59)-59(8-73)
73.(8-59)-59.(8-73)
=73.8-73.59-59.8+59.73
=(73.8-59.8)+(73.59-59.73)
=8.(73-59)+0
=8.14+0=112+0=0
Thực hiện phép tính rồi phân tích kết quả ra thừa số nguyên tố:
a, 75 + 58.50 – 58.25
b, 20: 2 2 – 5 9 : 5 8
c, 5 19 : 5 17 - 4 : 7
d, 47 - 45 . 2 4 - 5 2 . 12 : 14
e, 10 2 : 60 : 5 6 : 5 4 - 3 . 5
f, 2345 - 1000 : 19 - 2 21 - 18 2
g, 500 – {5.[409 – 2 3 . 3 - 21 2 ]+ 10 3 }:15
h, 967 – [8 + 2 . 3 2 – 24:6 + 9 - 7 3 ].5
a, 75 + 58.50 – 58.25 = 3.25 + 58.(50 – 25) = 3.25 + 58.25 = 25.(3+58) = 25.61 = 1525
Ta có: 1525 = 5 2 . 61
b, 20: 2 2 – 5 9 : 5 8 = 20:4 – 5 = 5 – 5 = 0
c, 5 19 : 5 17 - 4 : 7 = 5 2 - 4 : 7 = (25 – 4):7 = 3
d, 47 - 45 . 2 4 - 5 2 . 12 : 14 = 47 – (45.16 – 25.12):14 = 47 – (720 – 300):14 = 47 – 420:14 = 47 – 30 = 17
e, 10 2 : 60 : 5 6 : 5 4 - 3 . 5 = 100 – 60: 5 2 - 15 = 100 – 60:(25 – 15) = 100 – 60:10 = 100 – 6 = 94
Ta có: 94 = 2.47
f, 2345 - 1000 : 19 - 2 21 - 18 2 = 2345 – 1000:(19 – 2. 3 2 ) = 2345 – 1000:(19 – 2.9) = 2345 – 1000:(19 – 18) = 2345 – 1000:1 = 2345 – 1000 = 1345
Ta có: 1345 = 3.269
g, 500 – {5.[409 – 2 3 . 3 - 21 2 ]+ 10 3 }:15 = 500 – {5.[409 – 8 . 3 - 21 2 ]+1000}:15 = 500 – {5.[409 – 3 2 ]+1000}:15 = 500 – {5.(409 – 9)+1000}:15 = 500 – {5.400+1000}:15 = 500 – (2000+1000):15 = 500 – 3000:15 = 500 – 200 = 300
Ta có: 300 = 2 2 . 3 . 5 2
h, 967 – [8 + 2 . 3 2 – 24:6 + 9 - 7 3 ].5 = 967 – [8+2.9 – 4+8].5 = 967 – 30.5 = 967 – 150 = 817
Ta có: 817 = 19.43
\(73(8-59)-59(8-73)\)
73.(8-59)--59.(8-73)
73.-51-59.-65
-3723--3835
112
\(73\left(8-59\right)-59\left(8-73\right)\)\(=73.8-73.59-59.8+73.59\)
\(=\left(-73.59+73.59\right)+8\left(73-59\right)\)
\(=8.14=112\)
HỌC TỐT ><
\(73.\left(8-59\right)-59.\left(8-73\right)\)
\(=73.8-73.59-59.8+59.73\)
\(=59.\left(-73+73\right)+8\left(73-59\right)\)
\(=59.\left(73-73\right)+8.14\)
\(=0+112=112\)