Tính nhanh : \(\left(18.123+9.436.2+3.5310.6\right):\left(1+4+7+|11|+100-410\right)\)
Tính nhanh :
a) A = \(\dfrac{10\dfrac{1}{3}\left(26\dfrac{1}{3}-\dfrac{176}{7}\right)-\dfrac{12}{11}\left(\dfrac{10}{3}-1.75\right)}{\dfrac{5}{\left(91-0.25\right).\dfrac{60}{11}-1}}\)
b) ( 18.123+9.436.2+3.5310.6):(1+4+7+......+100-410)
tính nhanh (18.123+9.436.2+3.5310.6):(1+4+7+.......+100-410)
tính nhanh: ( 18.123+9.436.2+3.5310.6):(1+4+7+.....+100-410)
Tính nhanh: (18.123+9.436.2+3.5310.6) : ( 1+4+7+...+100-410 )
Ta có:
+) \(1+4+7+...+100=\left(1+100\right)+\left(4+97\right)+...+\left(49+52\right)\)(34 cặp)
\(=101.34=3434\)
+) \(3434-410=3024\)
+) \(\left(18.123+9.436.2+3.5310.6\right)=18\left(123+436+5310\right)\)
\(=18.5869=105642\)
Vậy \(A=105642:3024\approx34,93\)
Tính nhanh: (18.123 + 9.436.2 + 3.5310.6 ) : ( 1 + 4 + 7 + ....... + 100 - 410 )
Tính nhanh (18.123 + 9.436.2 + 3.5310.6) : (1 + 4 + 7 + ... + 100 - 410)
Tính nhanh
(18.123+9.436.2+3.5310.6):(1+4+7+...+100-410)
(18.123+9.436.2+3.5310.6)/(1+4+7+.....+100-410)
Tính nhanh:(18.123+9.436.2+3.5310.6):(1+4+7+...+100-410)
Ai giúp mình với!!!!
Phân tích: \(\left(18.123+9.436.2-3.3510.6\right)=18.123+18.436-18.5310\)\(\Leftrightarrow18.\left(123+436-3510\right)\)( chung số 18 )
\(\Leftrightarrow18.\left(-4751\right)=-85518\)
Tiếp tục phân tích vế sau:
\(\left(1+4+7+...+100-410\right)=\dfrac{\left[\left(100-1\right):3+1\right].\left(100+1\right)}{2}-410\)\(\Leftrightarrow1717-410=1307\)
\(\Leftrightarrow-85518:1717=\dfrac{-85518}{1717}\)
Vậy.............................