Out of the 400 emails that Antonia received in her mail, 1/4 were spam emails, while 2/5 of the remaining emails were promotional messages. If the rest of the emails were important emails, calculate the total number of important emails in her inbox.
Out of the 400 emails, 1/4*400 = 
<gadget id="calculator">400*1/4</gadget>
<output>100</output>
100 emails were spam emails.
The number of emails that were not spam emails is 400-100 = 
<gadget id="calculator">400-100</gadget>
<output>300</output>
300
2/5 of the emails which were not spam were promotional emails, a total of 2/5*300=
<gadget id="calculator">2/5*300</gadget>
<output>120</output>
120 emails.
If the rest of the emails were important emails, there were 300-120 = 
<gadget id="calculator">300-120</gadget>
<output>180</output>
180 important emails.

<result>180</result>