Tính nhanh:
a) 41. 36+ 59. 90 + 41. 84 + 59. 30
b) 4. 51 . 7 + 2 . 86 .7 + 6 . 4 . 7
c) ( 4.7 ) . 5 + ( 4.7 ) . 43 + ( 4.7) - 6
d) 53 . 39 + 47 . 39 - 53 . 21 - 47 . 21
Mọi người giúp em nhanh với, đag cần gấp lắm ạ. Cho em cả bài giải nữa nhé ạ!
Bài 1:tính nhanh
a,4*51*7+2*86*7+12*2
b,41*36+59*90+41*84+59*36
* là nhân nha các bạn
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?
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=?
Tính nhanh:
a) 29 . 30 + 21 . 30 - 150
b) 273 . 15 - 15 . 73 + 20 . 5
c) 41 . 36 + 59 . 90 + 41 . 84 + 59 . 30
d) 4 . 51. 7 + 2 . 86 . 7 + 12 . 2 .7
Giúp mình nha
tính
41 x 36 + 59 x 90 + 41 x 84 + 59 x 30
4 x 51 x 7 + 2 x 86 x 7 + 12 x 2 x 7
41 x 36 + 59 x 90 + 41 x 84 + 59 x 30
= 41 x (36 + 84) + 59 x ( 90 + 30 )
= 41 x 120 + 59 x 120
= 120 x ( 41 + 59 )
= 120 x 100
= 12000
4 x 51 x 7 + 2 x 86 x 7 + 12 x 2 x 7
= 7 x ( 51 x 4 + 86 x 2 + 12 x 2 )
= 7 x ( 204 + 172 + 24 )
= 7 x 400
=2800
41x 36 +59 x 90 +41 x84 +59 x 30
=41x (36+84) +59 x (90+30)
=41 x 120 + 59x 120
=120 x (41+59)
=120x 100
=12000
4x 51 x 7 + 2 x 86 x 7 + 12 x 2 x 7
=7x (51 x 4 + 86 x 2 - 12 x 2 )
=7x ( 204+ 172 + 24 )
= 7x 400
=2800
Ta có:
41 x 36 + 59 x 90 + 41 x 84 + 59 x 30
= 41 x (36+84) + 59 x (30+90)
=41 x 120+59 x 120
=(41+59) x 120=100 x 120=12000
4 x 51 x 7 + 2 x 86 x 7 + 12 x 2 x 7
=2 x 7 x (51 x 2+86+12)
=14 x 200
=2800
59-x/41+57-x/43+55-x/45+53-x/47+51-x/49=-5
\(\dfrac{59-x}{41}+\dfrac{57-x}{43}+\dfrac{55-x}{45}+\dfrac{53-x}{47}+\dfrac{51-x}{49}=-5\)
\(\Leftrightarrow\dfrac{59-x}{41}+1+\dfrac{57-x}{43}+1+\dfrac{55-x}{45}+1+\dfrac{53-x}{47}+1+\dfrac{51-x}{49}+1=0\)
=>100-x=0
hay x=100
tính nhanh
53* 39+47*39-53*21-47*21
2*53*12+4*6*87-3*8*40
5*7*77-7*60+49*25-15*42
53x39+47x39-53x21-47x21
=39x ( 53+47) - 21x(53+47)
=39 x100 - 21x100
= 100x(39-21)
=100x18
=1800
2x53x12 +4x6x87 - 3x8x40
= (2x12)x53 + (4x16)x87 - (3x8) x40
= 24x53 + 24x87 + 24x40
= 24( 53+87+40)
= 24x180
=4320
a,53*39+47*39-53*21-47*21
=39*[53+47]-21*[53+47]
=39*100-21*100
=3900-2100
=1800
b,2*53*12+4*6*87-3*8*40
=[2*12]*53+[4*6]*87-[3*8]*40
=24*53+24*87-24*40
=24*[53+87-40]
=24*100
=2400
tính nhanh:
a:53*39+47*39-53*21-47*21
b:2*53*12+4*6*87-3*8*40
c:5*7*77-7*60+49*25-15*42