1.tính hợp lí
a,7256-4375-725
————————-
3650+4375.7255
2.tìm x
a,55-x+33=76
b,476:x=28
c,[x+15].18=450
d,32.[43-x]=32
3.tính
a,75+25.7-247:19
b,21.12:[262-5.{347-296}]
c,[23.15-89-8].[432:24+11]ư
d,17+17.99
1.tính hợp lí
a,7256-4375-725
————————-
3650+4375.7255
2.tìm x
a,55-x+33=76
b,476:x=28
c,[x+15].18=450
d,32.[43-x]=32
3.tính
a,75+25.7-247:19
b,21.12:[262-5.{347-296}]
c,[23.15-89-8].[432:24+11]ư
d,17+17.99
Đáp án:
Giải thích các bước giải:
1, Tính hợp lý:
a, 7256-4375-725
=7256-(4375+725)
=2156
b, 3650+4375.7255
= 3650+ 31740625
= 31744275
2, Tìm x
a,55-x+33=76
55-x =76 – 33
55-x = 43
x = 55-43
x = 12
b,476 : x=28
x= 476 :28
x = 17
c,[x+15].18=450
x+15 = 450 : 18
x+15 = 25
x = 25-15
x = 10
d,32.[43-x]=32
43-x=32:32
43-x=1
x = 43-43
x =1
3, Tính
a, 75+25.7-247:19
= 75+175- 13
= 250- 13
= 237
b, 21.12:[262-5.{347-296}]
= 21.12:[262-5. 51]
= 21.12:[262-255]
= 21.12: 7
= 252:7
= 36
c,[23.15-89-8].[432:24+11]
=[345-89-8].[432:24+11]
=[ 256-8] . [18+11]
= 248 . 29
=7192
d,17+17.99
=17+1683
= 1700
Đáp án:
Giải thích các bước giải:
a,7256-4375-725
=7256-(4375+725)
=7256-5100
=2156
b 3650+4375.7255
=3560+31740625
=31744275
2
a
55-x+33=76
55-x=76-33
55-x=43
x=55-43
x=12
b
476:x=28
x=476:28
x=17
c
[x+15].18=450
x+15=450:18
x+15=25
x=25-15
x=10
d
32.[43-x]=32
43-x=32:32
43-x=1
x=43-1
x=42
3
a,75+25.7-247:19
=75+175-13
=250-13
=237
b,21.12:[262-5.{347-296}]
=21.12:[262-5.51]
=252:7
=36
c,[23.15-89-8].[432:24+11]
=[345-89-8].[18+11]
=248.29
=7192
d,17+17.99
=17.(1+99)
=17.100
=1700