1.实现两个数字的加减乘除
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</head><body><script>let num1 = prompt('请输入第一个数字：')let fh = prompt('请输入符号')let num2 = prompt('请输入第二个数字：')switch(fh) {case '+': alert(parseFloat(num1) + parseFloat(num2));break;case '-': alert(num1 - num2);break;case '*': alert(num1 * num2);break;case '/': alert(num1 / num2);break;}</script>
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