Tinh bang cach hop li:
a, 47.33 + 47 + 66.47
b, 24.57 + 43.24
c, 387.2694 + 7305.387 + 387
d, 563.78 - 26.563 + 563.48
ai nhanh dc tik :P
Tinh hop li:
47.173 + 47- 47.74
47.33 + 47 + 66.47
24.57 + 43.24
387.2694 + 7305.387 + 387
12.19 + 12
195.56 + 43.105 + 195
47.173 + 47 - 47.74
= 47.( 173 + 1 - 74 )
= 47. 100
= 4700
47.33 + 47 + 66.47
24.57 + 43.24
387.2694 + 7305.387 + 387
12.19 + 12
195.56 + 43.105 + 195
Tính hợp lí:
a) 13.57 + 43.13
b) 39.28 + 39.72
c)345.67 - 245.67
d) 123.34 + 123.26 + 123.40
e) 974.34 + 974.96 - 974.30
f) 37.148 - 37.53 + 37.5
g) 47.173 + 47 + 66.47
h) 24.57 + 43.24
i) 387.2694 + 7305.387 + 387
a) 13 . 57 + 43.13 = 13.(57 + 43)
= 13 . 100 = 1300
b) 39 . 28 + 39 . 72 = 39 . (28 + 72)
= 39 . 100 = 3900
c) 345 . 69 - 245 . 67 = (345 - 245) . 67
= 100 . 67 = 6700
d) 123 . 34 + 123 . 26 + 123. 40 = 123 . (34 + 26 + 40)
= 123 . 100 = 12300
e) 974 . 34 + 974 . 96 - 974 . 30 = 974 . (34 + 96 - 30)
= 974 . 100 = 97400
f) 37 . 148 - 37 . 53 + 37 . 5 = 37 . (148 - 53 + 5)
= 37 . 100 = 3700
9) 47 . 173 + 47 + 66.47 = 47 . (173 + 1 + 66)
= 47 . 240 = 11280
h, i ) tự làm
387.2694+7305.387+387
nhanh lên like dang đợi
387.2694+7305.387+387
=387.2694+7305.387+387.1
=387.(2694+7305+1)
=387.10000
=3870000
Tinh hop li:
a) 89.99 + 11.99
b) 125.43 - 25.43
c) 156.53 + 156.47
d) 567.27 + 57.567 + 16.567
e) 563.78 - 26.563 + 16.567
f) 39.156 - 39.57+ 39
g) 56.37 + 37.189 - 145.37
h) 123.46 + 123.78 - 123.37 +123.3
i) 12.19+ 12
k) 195.56 + 43. 105 + 195
a) 89.99 + 11.99= 99(89+11)= 99.100=9900
b) 125.43 - 25.43= 43(125-25)=43.100=4300
c) 156.53 + 156.47=156(53+47)= 156.100=15600
d) 567.27 + 57.567 + 16.567=567(27+57+16)= 567.100=56700
f) 39.156 - 39.57+ 39= 39(156-57+1)=39.100
g) 56.37 + 37.189 - 145.37=37.(56+189-145)= 37.100=3700
h) 123.46 + 123.78 - 123.37 +123.3=123(46+78-37+3)=123.90=11070
i) 12.19+ 12=12(19+1)= 12.20=240
tk mik nhá
tính tổng
a)387.2694+7305.387+387
387.2694+7305.387+387
=387.2694+7305.387+38.1
=387.(2694+7305+1)
=387.10000
=3870000
a)387.2694+7305.387+387
= 387.2694+7305.387+387.1
=387.(2694+7305+1)
=387.10000
=3870000
Tinh gia tri cua cac bieu thuc sau bang cach hop li
a) 125 : (-61) . (-23) . (-1) 2n
b) 136 . (-47) + 36 . 47
Co the tinh nhanh tong 37+198 bang cach ap dung tinh chat ket hop cua phep cong
37 + 198 = (37 - 2) + (198 + 2) = 35 + 200 = 235
37 + 198 = 37 + 63 + 35 + 100
= 100 + 100 +35
= 200 + 35
= 235
37 + 198 = 37+ 63 + 35 + 100
= 100 + 100 + 35
= 200 + 35
= 235
Tinh tong sau bang cach hop ly:
B = 5/2.1 + 4/1.11 + 3/11.2 + 1/2.15 + 13/15.4
Ghi ca cach lam nhe ! Ai nhanh nhat, dung nhat tick lun !!!!!!
B= (5/2.1 + 4/1.11 + 3/11.2 )+(1/2.15 +13/15.4)
B= (55/22 + 8/22 + 3/22) + ( 2/4.15 + 13/15.4 )
B= 3 + 15/15.4 = 3+1/4 = 13/4
tinh bang cach hop ly
21x35x3x25x7
\(21\cdot35\cdot3\cdot25\cdot7\)
\(=21\cdot3\cdot7\cdot35\cdot25\)
\(=21(3\cdot7)\cdot35\cdot25\)
\(=21\cdot21\cdot35\cdot25\)
\(=21^2\cdot875=385875\)
Nghĩ sao không có số nào tròn để tính hợp lí -_-