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a) 135 x (20 + 3)
= 135 x 20 + 135 x 3
= 2700 + 405 = 3105
427 x (10 + 8)
= 427 x 10 + 427 x 8
= 4270 + 3416 = 7686
b) 642 x (30 -6)
= 642 x 30 - 642 x 6
= 19260 - 3852 = 15408
287 x (40 -8)
= 287 x 40 - 287 x 8
= 11480 - 2296 = 9184
135 x ( 20 + 3 ) = 135 x 23 = 3105
427 x ( 10 + 8 ) = 427 x 18 = 7686
642 x ( 30 - 6 ) = 642 x 24 = 15408
287 x ( 40 - 8 ) = 287 x 32 = 9184
135x(20+3)=3105
427x(10+8)=7686
642x(30-8)=15408
287x(40-8)=9184
a)135 x (20+3)=3105 b)642 x (30 - 6)=15408
427 x (10+8)=7650 287 x (40 - 8)=9184
a: =24*1000=24000
b: =120*1000=120000
c: =72(135+65):25-140
=72*8-140=436
d: =18(957-354-621):72=-9/2
\(\frac{1}{10}+\frac{2}{20}+\frac{3}{30}+\frac{4}{40}+\frac{5}{50}+\frac{6}{60}+\frac{7}{70}+\frac{8}{80}+\frac{9}{90}\)
\(=\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}\)
\(=\frac{9}{10}\)
`1/2+2/4+3/6+4/8+5/10+6/12`
`=1/2+1/2+1/2+1/2+1/2+1/2`
`=1/2*6=3`
`1/3+1/4+1/5+8/10+20/15+20/30`
`=(1/3+1/4)+(1/5+4/5)+(4/3+2/3)`
`=7/12+1+2`
`=7/12+3=43/12`
\(\dfrac{1}{2}+\dfrac{2}{4}+\dfrac{3}{6}+\dfrac{4}{8}+\dfrac{5}{10}+\dfrac{6}{12}\)
\(=\dfrac{1}{2}+\dfrac{1}{2}+\dfrac{1}{2}+\dfrac{1}{2}+\dfrac{1}{2}+\dfrac{1}{2}\)
\(=\dfrac{1}{2}\times6=3\)
\(------\)
\(\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{8}{10}+\dfrac{20}{15}+\dfrac{20}{30}\)
\(=\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{4}{5}+\dfrac{4}{3}+\dfrac{2}{3}\)
\(=\left(\dfrac{1}{3}+\dfrac{4}{3}+\dfrac{2}{3}\right)+\left(\dfrac{1}{5}+\dfrac{4}{5}\right)+\dfrac{1}{4}\)
\(=\dfrac{7}{3}+1+\dfrac{1}{4}\)
\(=\dfrac{28}{12}+\dfrac{12}{12}+\dfrac{3}{12}\)
\(=\dfrac{43}{12}\)
135 x (20 + 3)
= 135 x 20 + 135 x 3
= 2700 + 405
= 3105.
427 x (10 + 8)
= 427 x 10 + 427 x 8
= 4270 + 3416
= 7686.
642 x (30 - 6)
= 642 x 30 - 642 x 6
= 19260 - 1452
= 18808.
287 x (40 - 8)
= 287 x 40 - 287 x 8
= 11480 - 2296
= 9184.
135x(20+3) 642 x (30-6)
= 135 x 20 + 135 x 3 = 642 x 30 - 642 x 6
= 2700+405 = 19 260 - 3852
= 3105 =15 408
427 x ( 10+8) 287 x (40 - 8)
= 427 x 10 + 427 x 8 = 287 x 40 - 287 x 8
= 4270 + 3416 =11 480 - 2296
=7686 = 9184