Toán Lớp 6: Tính nhanh:
A) -75•(5^7-34)-57•(34-75)
B)-2019+12•(-76)-76•(-34)
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Toán Lớp 6: Tính nhanh:
A) -75•(5^7-34)-57•(34-75)
B)-2019+12•(-76)-76•(-34)
Comments ( 1 )
a) – 75.\left( {57 – 34} \right) – 57.\left( {34 – 75} \right)\\
= – 75.57 + 75.34 – 57.34 + 57.75\\
= \left( { – 75 + 57 + 57.75} \right) + 75.34 – 57.34\\
= 0 + 34.\left( {75 – 57} \right)\\
= 34.18\\
= 612\\
b)\\
– 2019 + 12.\left( { – 76} \right) – 76.\left( { – 34} \right)\\
= – 2019 – 76.12 + 76.34\\
= – 2019 + 76.\left( { – 12 + 34} \right)\\
= – 2019 + 76.22\\
= – 2019 + 1672\\
= – 347
\end{array}$