I don't know why my code is not passing test 8 and 10

My calculator displays the input on the screen and also user can’t start with zero

Follow the errors. For #8:

Numbers do not display correctly within id="display" : expected '123\n123' to equal '123'

Here’s your display:

        <div id="display" className="displayexpression">
          <h1>{this.state.display}</h1>
          <h2>{this.state.result}</h2>{" "}
        </div>

which means that when the test enters 123, your element with id="display" will have

123
123

when the tags are stripped as in the test. Since that is not 123 as the test expects, it fails. The same thing is happening on #10.