Toán a) 5 + 8 + 11 +14 +…+ 302 b) 7 + 11 + 15 + 19 +…+ 203 01/10/2021 By Athena a) 5 + 8 + 11 +14 +…+ 302 b) 7 + 11 + 15 + 19 +…+ 203
$\begin{array}{l} a)\,\,\,A = 5 + 8 + 11 + 14 + + ….. + 302\\ Ta\,\,thay\,\,A\,\,la\,\,tong\,\,cua\,\,cac\,\,so\,\,cach\,\,nhau\,\,3\,\,don\,\,vi.\\ So\,\,cac\,\,so\,\,hang\,\,cua\,\,A:\,\,\,\,\left( {302 – 5} \right):3 + 1 = 100.\\ \Rightarrow A = \left( {302 + 5} \right).100:2 = 15350.\\ b)\,\,\,B = 7 + 11 + 15 + 19 + …. + 203\\ Ta\,\,thay\,\,B\,\,la\,\,tong\,\,cua\,\,cac\,\,so\,\,cach\,\,nhau\,\,4\,\,don\,\,vi.\\ So\,\,cac\,\,so\,\,hang\,\,cua\,\,B:\,\,\,\,\left( {203 – 7} \right):4 + 1 = 50.\\ \Rightarrow A = \left( {203 + 7} \right).50:2 = 5250. \end{array}$ Trả lời
a) SSH: (302-5) /3+1 =100 Tổng: (302+5) * 100/2= 15350 b)SSH: (203-7)/4+1= 50 Tổng: (203+7) *50/2 =5250 Trả lời
$\begin{array}{l}
a)\,\,\,A = 5 + 8 + 11 + 14 + + ….. + 302\\
Ta\,\,thay\,\,A\,\,la\,\,tong\,\,cua\,\,cac\,\,so\,\,cach\,\,nhau\,\,3\,\,don\,\,vi.\\
So\,\,cac\,\,so\,\,hang\,\,cua\,\,A:\,\,\,\,\left( {302 – 5} \right):3 + 1 = 100.\\
\Rightarrow A = \left( {302 + 5} \right).100:2 = 15350.\\
b)\,\,\,B = 7 + 11 + 15 + 19 + …. + 203\\
Ta\,\,thay\,\,B\,\,la\,\,tong\,\,cua\,\,cac\,\,so\,\,cach\,\,nhau\,\,4\,\,don\,\,vi.\\
So\,\,cac\,\,so\,\,hang\,\,cua\,\,B:\,\,\,\,\left( {203 – 7} \right):4 + 1 = 50.\\
\Rightarrow A = \left( {203 + 7} \right).50:2 = 5250.
\end{array}$
a) SSH: (302-5) /3+1 =100
Tổng: (302+5) * 100/2= 15350
b)SSH: (203-7)/4+1= 50
Tổng: (203+7) *50/2 =5250