Adding values in textboxes

I have 4 textboxes that will have values put into them and then I want a 5th textbox to add them up. I put 150 into each box and would get a value in the 5th box of 450150. So it was adding the first three and then concoting the 4th box. So I tried to add the first two and the second two then add them together and got 300300. Below is the code that I am using.
protected void Page_Load(object sender, EventArgs e) { Solictot.Text = (Convert.ToDecimal(item1txt1.Text) + Convert.ToDecimal(item2txt1.Text)) + (Convert.ToDecimal(item3txt1.Text) + Convert.ToDecimal(item4txt1.Text)).ToString(); }
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