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Calculati:a)3+2·[tex] \frac{1}{5} [/tex]
             b)5-3·[tex] \frac{1}{4} [/tex]
             c)[tex] \frac{3}{2} [/tex]+[tex] \frac{3}{4} [/tex]·[tex] \frac{1}{2} [/tex]
             d)[tex] \frac{1}{2} [/tex]+2·(0,25+3)
             e)3,25-3·(1,7-[tex] \frac{3}{2} [/tex])

Răspuns :

ValyRemus
a.) 15 / 5 + 2 / 5 = 17 / 5
b.) 20 / 4 - 3 / 4 = 17 / 4
c.) 3 / 2+ 3 / 8 = 12 / 8 + 3 / 8 = 15 / 8
d.) 0,5 + 2 * 3.25 = 0,5 + 6,5 = 7
e.) 3.25 - 3 (1.7 - 1.5) = 3.25 - 3* 0.2 = 3.25 - 0.6 = 2. 65
Economist
a) 3 + 2 · 1/5 = 3 + 2/5 = 3·5 / 5 + 2/5 = 15/5 + 2/5 = ( 15 + 2) / 5 = 17/5
b) 5 - 3 intregi 1/4 = 5 - ( 3·4 + 1) / 4 = 5 - 13/5 = 5·5 /5  - 13/5 = 25/5 - 13/5 =
     = ( 25 - 13) / 5 = 12/5
c) 3/2 + 3/4 · 1/2 = 3/2 + 3 /8 = 3·4 /8 + 3/8 = 12/ 8 + 3 /8 = ( 12 + 3) / 8
     = 15 /8
d) 1/2 + 2 ·( 0,25 + 3) = 1/2 + 2· 3,25 = 1/2 + 6,5 = 1/2 + 65/ 10 = 1/2 + 13/2
     = ( 1 + 13) / 2 = 14 / 2 = 7
e) 3,25 - 3 ·( 1,7 - 3/2)= 3,25 - 3· ( 17/10 - 3/2)
     = 3,25 - 3· ( 17/10 - 3·5/10) = 3,25 - 3· ( 17/10 - 15/10) =
     = 3,25 - 3· 2/10 = 3,25 - 3 ·1/5 = 3,25 - 3/5 = 325/100 - 3/5
     = 65/20 - 3/5 = 13/ 4 - 3/5 = 13·5 /20  -  3·4 / 20=
     = 65/20  - 12/20 = 53/20