Toán Lớp 6: bỏ dấu ngoặc rồi tính
a.(35+75)+(345-35-75)
b.(2002-79+15)-(-79+15)
c.-(515-80+91)-(2003+80-91)
d.32+34+36+38-(10-12 -16-14-18)
giúp mik mik vote 5 sao
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Toán Lớp 6: bỏ dấu ngoặc rồi tính
a.(35+75)+(345-35-75)
b.(2002-79+15)-(-79+15)
c.-(515-80+91)-(2003+80-91)
d.32+34+36+38-(10-12 -16-14-18)
giúp mik mik vote 5 sao
Comments ( 2 )
a.\left( {35 + 75} \right) + \left( {345 – 35 – 75} \right)\\
= 35 + 75 + 345 – 35 – 75\\
= \left( {35 – 35} \right) + \left( {75 – 75} \right) + 345\\
= 0 + 0 + 0345\\
= 345\\
b.\left( {2002 – 79 + 15} \right) – \left( { – 79 + 15} \right)\\
= 2002 – 79 + 15 + 79 – 15\\
= 2002 + \left( { – 79 + 79} \right) + \left( {15 – 15} \right)\\
= 2002 + 0 + 00\\
= 2002\\
c. – \left( {515 – 80 + 91} \right) – \left( {2003 + 80 – 91} \right)\\
= – 515 + 80 – 91 – 2003 – 80 + 91\\
= – 515 + \left( {80 – 80} \right) + \left( { – 91 + 91} \right) – 2003\\
= – 515 + 0 + 0 – 2003\\
= – 2518\\
d.32 + 34 + 36 + 38 – \left( {10 – 12{\rm{ }} – 16 – 14 – 18} \right)\\
= 32 + 34 + 36 + 38 – 10 + 12 + 16 + 14 + 18\\
= \left( {32 + 18} \right) + \left( {34 + 16} \right) + \left( {36 + 14} \right) + \left( {38 + 12} \right) – 10\\
= 50 + 50 + 50 + 50 – 10\\
= 190\\
\end{array}\]