Question

Tính A

A=2.4 + 4.6 + ..... + 98.100

Answer 1

\(A=2.4+4.6+6.8+...+96.98+98.100\)

\(\Rightarrow6A=2.4.6+4.6.8-2.4.6+6.8.10-4.6.8+...+96.98.100-94.96.98+98.100.102-96.98.100\)

\(\Rightarrow6A=\left(2.4.6+4.6.8+6.8.10+...+96.98.100+98.100.102\right)-\left(2.4.6+4.6.8+...+94.96.98+96.98.100\right)\)\(\Rightarrow6A=98.100.102\)

\(\Rightarrow A=\frac{98.100.102}{6}=98.100.17=166600\)

P/s: Ko chắc

Answer 2

Tham khảo tại : https://h.vn/hoi-dap/question/487224.html

Câu hỏi của Kanzaki Mizuki -toán lớp 6