tính nhanh
a) 21 . 78 + 21 . 23 -21
b) 57 . 64 - 57 .3 + 39.57
c) 47.29 - 13 .29 - 24.29
d) 12.53 + 53 .172 - 53. 84
e) 24.42 - 35 .24 - 24.7
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70=?
2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40 = ???
12 . 25 + 29 . 25 + 59 . 25 = ???
43 . 37 + 93 . 43 + 57 . 61 + 69 . 57 = ???
12 . 53 + 53 . 172 - 53 = ???
35 . 54 + 35 . 58 + 65 . 75 + 65 . 45 = ???
39 . 8 + 70 . 3 + 31 . 8 = ???
2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40
= 2. 53 . 9 . 3 + 2. 3 .9 .87 - 3 .2 .9 .40
= 54.53+54.87-54.40
=54(53+87-40)
=54. 100=5400
12 . 25 + 29 . 25 + 59 . 25
= 25 . ( 12+29+59)
=25 . 90
=2250
43 . 37 + 93 . 43 + 57 . 61 + 69 . 57
= 43.(37+93)+57(61+69)
=43.130+57.130
=130.(43+57)
=130.100
=13 000
12 . 53 + 53 . 172 - 53
=53(12+172-1)
=53.184
=9752
35 . 54 + 35 . 58 + 65 . 75 + 65 . 45
=35(54+58)+65(75+45)
=35.112+65.120
=3920+7800
=11720
39 . 8 + 70 . 3 + 31 . 8
=8(39+31)+70.3
=8.70+70.3
=70.(8+3)
=70.11
=770
2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40
= ( 2 . 27 ) . 53 + ( 6 . 9 ) . 87 - ( 3 . 18 ) . 40
= 54 . 53 + 54 . 87 - 54 . 40
= 54(53+87-40)
= 5400
12 . 25 + 29 . 25 + 59 . 25
= 25( 12 + 29 + 59 )
= 2500
43 . 37 + 93 . 43 + 57 . 61 + 69 . 57
= 43( 37 + 93 ) + 57(61 + 69 )
= 5590 + 7410
= 13000
12 . 53 + 53 . 172 - 53
= 53( 12 + 172 ) - 53
= 9752 - 53
= 9699
35 . 54 + 35 . 58 + 65 . 75 + 65 . 45
= 35( 54 + 58 ) + 65( 75 + 45 )
= 3920 + 7800
= 11720
số 1 tính nhanh A 78 x 31 78 x 24 78 x 17 22 x 72C 53 x 39 47 x 39 53 x 21 47 x 21B 35 x 34 35 x 86 65 x 75 65 x 45D 27 x 332 68 x 27 73 x 332 68 x 73E 2 x 53 x 12 4 x 6 x 37 2 x 38 x 12F 3 x25 x 8 4 x 6 x 37 2 x 38 x 12
tính nhanh hợp lí nếu có thể
a,[(-19)+(-3)]+[(-60)+45]+[(-7)+10]+(13+5)23)+13+(-17)+57
b,(871-28)+(-2004+28-871)
c,69+53+46+(-94)+(-14)+78
d,-11+23-(-21)
e,1-2+3-4+...-98+99
f,123)+|-13|+(-7)
h.-33|+(-15)+20-|45-40|-57
1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11 * 12 * 13 * 14 * 15 * 16 * 17 * 18 * 19 * 20 * 21 * 22 * 23 * 24 * 25 * 26 * 27 * 28 * 29 * 30 * 31 * 32 * 33 * 34 * 35 * 36 * 37 * 38 * 39 * 40 * 41 * 42 * 43 * 44 * 45 * 46 * 47 * 48 * 49 * 50 * 51 * 52 * 53 * 54 * 55 * 56 * 57 * 58 * 59 * 60 * 61 * 62 * 63 * 64 * 65 * 66 * 67 * 68 * 69 * 70 * 71 * 72 * 73 * 74 * 75 * 76 * 77 * 78 * 79 * 80 * 81 * 82 * 83 * 84 * 85 * 86 * 87 * 88 * 89 * 90 * 91 * 92 * 93 * 94 * 95 * 96 * 97 * 98 * 99 * 100 bằng bao nhiêu?
Bai 1 : So sanh :
a ) - 23 / -17 va -13 / -17
b ) -57 / 53 va -97 / 93
c ) -21 / 29 va 81 / -89
TICK NHA .
a) -23/-17 = 23/17
-13/-17 = 13/17
Vì 23>13 => 23/17>13/17
Vậy -23/-17>-13/-17
b) -57/53 = -5301/4929
-97/93 = -5141/4929
Vì -5301<-5141 => -5141/4929< -5301/4929
Vậy -97/93<-57/53
c) 81/-89 = -81/89
-21/29 = -1869/2581
-81/89 = -2349/2581
Vì -1869>-2349 => -2349/2581>-1869/2581
Vậy 81/-89>-21/29
Tính nhanh
a) 78*31+78*24+78*17+22*72
b) 53*39 +47*39-53*21-47*21
b, 53.39 + 47.39 - 53.21 - 47.21
= 39( 53 + 47) - 21 53 + 47)
= 39.100 - 21.100
= 100(39 - 21)
= 100. 18
= 1800
bấm cho mình đúng nha ^_^
a)=78.(31+24+17)+22.72
=72.(78+22)
=72.100
=7200
b)=39.(53+47)-21.(53+47)
=100.(39-21)
=100.18
=1800
Tính nhanh
a) 78*31+78*24+78*17+22*72
b) 53*39 +47*39-53*21-47*21
Bài 2:Bỏ dấu ngoặc rồi tính:
1) (12+21)-(23-21+10)
2) (57-725)-(605-53)
3) (55+45+15)-(15-55+45)
Bài 5. Điền dấu “>, <, =” vào chỗ chấm cho thích hợp:
a) (−56)+(−16)….(−40)
b) 9+|−33|…14+|−28|
c) (−47)…(−24)+(−23)
d) (-85) ...... (-67) + (-19)
e) (-35) + 28 ...... 35 + (-28)
f) 64 + (-36) + (-24) ..... 4
g) (-28) + (-13) ..... (-29) + (-13)
h) (-21) + (-19) ...... 0 ...... |-21| + |-19|
i) (-92) + 46 ....... 17 + 68
j) 53 + (-53) ....... (-2014) + 2014