Question

[Cửu vĩ linh hồ Kurama]

Tính nhanh:

a/ 35.34+35.86+65.75+65.45

b/ 21.7² - 11.7²+90.7²+49.125.16

Answer 1

[BW_P&A]

a)

\(\Rightarrow35.\left(34+86\right)+65.\left(75+45\right)\)

\(\Rightarrow35.120+65.120\)

\(\Rightarrow120.\left(35+65\right)=120.100=12000\)

b)

\(\Leftrightarrow21.49-11.49+90.49+49.125.16\)

\(\Rightarrow49.\left(21-11+90+2000\right)\)

\(\Rightarrow49.2100=102900\)

Answer 2

[Nguyễn Thị Khánh Linh]

a) 35 . 34 + 35 . 86 + 65 . 75 + 65 . 45
= 35 . ( 34 + 86 ) + 65 . ( 75 + 45 )
= 35 . 120 + 65 . 120
= ( 35 + 65 ) . 120
= 100 . 120
= 12000