tính nhanh: (25-12 ) x ( 25- 22) x ... x ( 25-1002)
Tính nhanh:
a) 78 x 13 +13 x 22
b) 25 x 70 + 28 x 25 + 50
c) ( 45 x 28 x 19 ) : ( 19 x 14 x 15)
d) ( 132 x70 x60 ) : ( 12 x 35 x 20 )
GIÚP MÌNH VỚI Ạ ,MÌNH ĐANG CẦN GẤP
\(a.13.\left(78+22\right)=13.100=1300\)
\(b.25.70+28.25+25.2=25.\left(70+28+2\right)=25.100=2500\)
\(c.\dfrac{15.3.14.2.19}{19.14.15}=6\)
\(d.\dfrac{132.70.60}{12.35.20}=\dfrac{11.12.35.2.20.3}{12.35.20}=66\)
Tính nhanh:
12345 x 22 + 12345 x 38 + 12345 x 25 + 12345 x 15
12345 x 17 + 23 x 12345 + 12345 + 12345 x 35 + 12345 x 24
= 12345 x 17 + 23 x 12345 + 12345 x 1 + 12345 x 35 + 12345 x 24
= 12345 x (17 + 23 + 1 + 35 + 24)
= 12345 x 100
= 1234500
TÍNH NHANH
12 , 48 : 0, 5 x 6 , 25 x 4 x 2
-------------------------------------------
2 x 3 , 12 x 1 , 25 : 0 , 25 x 10
tính
5/8 x 16 /7 x 21/25
11/12 : 22/30 x 6 /15
5/8x16/7x21/25
=1/1x2/1x3/5
=6/5
11/12:22/30x6/15
=11/12x30/22x6/15
=1/2x1/2x1/2
=1/8
5/8x16/7x21/25
=1/1x2/1x3/5
=6/5
11/12:22/30x6/15
=11/12x30/22x6/15
=1/2x1/2x1/2
=1/8
Tính nhanh :
3/4 x 4/9 x 9/11 x 22/25 x 5/7 : 10/7
\(=\dfrac{3}{9}\cdot\dfrac{9}{11}\cdot\dfrac{22}{25}\cdot\dfrac{5}{7}\cdot\dfrac{7}{10}=\dfrac{3}{11}\cdot\dfrac{22}{25}\cdot\dfrac{5}{10}=3\cdot2\cdot\dfrac{1}{2}\cdot\dfrac{1}{5}=\dfrac{3}{5}\)
\(=\dfrac{3x4x9x11x2x5x7}{4x9x11x5x5x10}=\dfrac{3x2x7}{10}=\dfrac{42}{10}=\dfrac{21}{5}\)
=3/9⋅9/11⋅22/25⋅5/7⋅7/10=3/11⋅22/25⋅5/10=3⋅2⋅1/2⋅1/5=3/5
1) So sánh phân số:
23/27 và 22/29
12/25 và 25/49
2) Tính nhanh
254 x 399 - 145/254 + 399 x 253
5932+6001 x 5931/5932 x 6001 - 69
Rất mong các bn giúp đỡ! Cảm ơn rất nhiều!
tính nhanh
25 x 323 - 22 x 25 -25
\(25\times323-22\times25-25\\ =25\times\left(323-22-1\right)\\ =25\times300\\ =7500\)
\(=25.\left(323-22-1\right)\)
\(=25.300=7500\)
b: =2376-376+3425-42
=2000+3383
=5383
c: =3145-145+246+4246+2347-347
=3000+2000+4492
=9492
e: =(72-72):A=0