Function checkNumber

test/compute-engine/canonical-form.test.ts:703–704

(input: string | ExpressionInput)

        canonical  = ["Sqrt", ["Multiply", 7, ["Sqrt", 13]]]
      `);
      //note: for the following two cases, 'fully'-canonical transforms 'Divide -> Multiply' (this
      //being preferred to facilitate further ops.)
      expect(checkPower('{a/3}^{1/3}')).toMatchInlineSnapshot(`
        box        = ["Power", ["Divide", "a", 3], ["Divide", 1, 3]]
        canonForms = ["Root", ["Divide", "a", 3], 3]