12×125×54
b.64×125×54
c.36×[143+57)+64+(143+57)
d.78×31+78×24+70×22×22×72
e.64×14+9×59
a)78*31+78*24+78*17+22*17
b)64*14+9*56
a) 78 . 31 + 78 . 24 + 78 . 17 + 22 . 17
= 78 . (31 + 24) + 17 . (78 + 22)
= 78 . 55 + 17 . 100
= 4290 + 1700
= 5990
b) 64 . 14 + 9 . 56
= 64 . 14 + 9 . 14 . 4
= 14 . (64 + 9 . 4)
= 14 . 100
= 1400
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=?
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 tính hợp lý
36 * (143+57) +64 * ( 143+57 )
36 * (143 + 57) + 64 * (143 + 57)
= (143 + 57) * (36 + 64)
= 200 * 100
= 20000
\(36\times\left(143+57\right)+64\times\left(143+57\right)=\left(143+57\right)\times\left(36+64\right)\)
\(=200\times100=20000\)
36 * ( 143 +57 ) +64 * ( 143 +57 ) = 36 * 200 + 64 * 200
= 200 * ( 36 + 64 )
= 200 * 100
= 20000
Tính nhanh:
a) 64+469+31+36
b) 25×2018×4
c) 325×78+325×22
d) 9×11×53+33×66×3+99
e) 259×268-259×168
f) 25×6×4×125×8
hello; how are you
a)
= (64 + 36) + (469 + 31)
= 100 + 500
= 600
b)
= 25 . 2018 . 4
= (25 . 4) . 2018
= 100 . 2018
= 201800
Tính nhanh:
36.(146+57)+64.(143+57)
Tính nhanh :
36 . ( 146 + 57 ) + 64 . ( 143 + 57 )
36. (146+57) +64 . 200
36.203+64.200
7308+12800
=20108
36 . ( 146 + 57 ) + 64 . ( 143 + 57 )
= 36 . 146 + 57 + 64 . 143 + 57
= 36 . 146 + 143 + 57
= 36 . ( 146 + 143 + 1 )
= 36 . 290
= 10440
Tính hợp lý, biết:
36.(146+57)+64.(143+57)
=36.(143+3+57)+64.200
=36.200+36.3+64.200
=(36+64).200+108
=100.200+108
=20000+108=20108