\[\boxed{\mathbf{224.}}\]
\[450 + 50 = 500 > 450 - 50 =\]
\[= 400\]
\[640 - 20 = 620 > 640 - 200 =\]
\[= 440\]
\[380 + 20 = 400 > 380 - 20 =\]
\[= 360\]
\[545 - 40 = 505 < 545 - 45 =\]
\[= 500\]