\(98+98\cdot100-101\cdot98\)

\(=98\cdot1+98\cdot100-101\cdot98\)

\(=98\cdot1+100\cdot98-101\cdot98\)

\(=98\cdot\left(1+100-101\right)\)

\(=98\cdot0\)

\(=0\)

\(1.\) \(money\)

\(2.\) \(moon\)

\(3.\) \(mother\)

\(4.\) \(monday\)

\(5.\) \(morning\)

\(6.\) \(meet\)

\(7.\) \(meat\)

\(8.\) \(milk\)

\(9.\) \(move\)

\(10.\) \(much\)

\(11.\) \(main\)

\(12.\) \(mood\)

\(13.\) \(mess\)

\(14.\) \(mile\)

\(15.\) \(mate\)

     Số vải may quần là \(:\)

          \(345\cdot40:100=138\) (m)

     Số vải may áo là \(:\)

          \(345-138=207\) (m)

               Đáp số \(:\) \(207\) (m)      

Là am, is, are

\(\dfrac{a}{b}:\dfrac{1}{2}\cdot\dfrac{3}{4}=\dfrac{6}{5}\)

\(\dfrac{a}{b}:\dfrac{1}{2}=\dfrac{6}{5}:\dfrac{3}{4}\)

\(\dfrac{a}{b}:\dfrac{1}{2}=\dfrac{6}{5}\cdot\dfrac{4}{3}\)

\(\dfrac{a}{b}:\dfrac{1}{2}=\dfrac{24}{15}\)

\(\dfrac{a}{b}:\dfrac{1}{2}=\dfrac{8}{5}\)

\(\dfrac{a}{b}=\dfrac{8}{5}\cdot\dfrac{1}{2}\)

\(\dfrac{a}{b}=\dfrac{4}{5}\)

Vậy \(a=4,b=5\)

Số số hạng là :

( \(2005-1\) ) \(:1+1=2005\)

Tổng dãy số :

\(\left[\left(2005+1\right)\cdot2005\right]:2\)

\(=2006\cdot2005:2\)

\(=4022030:2\)

\(=2011015\)

\(a\)) \(x\) x \(\dfrac{4}{5}=\dfrac{3}{4}-\dfrac{2}{5}\)

\(x\) x \(\dfrac{4}{5}=\dfrac{15}{20}-\dfrac{8}{20}\)

\(x\) x \(\dfrac{4}{5}=\dfrac{7}{20}\)

\(x=\dfrac{7}{20}:\dfrac{4}{5}\)

\(x=\dfrac{7}{20}\) x \(\dfrac{5}{4}\)

\(x=\dfrac{35}{80}\)

\(x=\dfrac{7}{16}\)

\(b\)) \(x:\dfrac{3}{5}=\dfrac{5}{7}+1\)

\(x:\dfrac{3}{5}=\dfrac{5}{7}+\dfrac{7}{7}\)

\(x:\dfrac{3}{5}=\dfrac{12}{7}\)

\(x=\dfrac{12}{7}\) x \(\dfrac{3}{5}\)

\(x=\dfrac{36}{35}\)