Zhang Ming's mother's salary income in April this year is 1,250 yuan. After deducting 800 yuan, she pays personal income tax at a rate of 5%. How much personal income tax should Zhang Ming's mother pay?
张明妈妈今年四月的工资收入是1250元，扣除800元后按5%的税率缴个人所得税．张明妈妈应缴个人所得税多少元？
<gadget id="calculator">1_250 - 800</gadget>
<output>450</output>

<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">450 * (1/20)</gadget>
<output>45/2 = around 22.5</output>

<result>45/2 = around 22.5</result>