40×25= 6×99+6=120÷40+9= 3600÷60=(380﹣300)÷5= 3×6+5×6=51÷17= 500÷25+8=4300÷(25×43)=
36.3×5.5+6.37×55.
999×999﹣2×999+1.
2.5×(1.9+1.9+1.9+1.9)
÷20.
2008×+200.8×4.3+20.08×8.