To synthesise 1 mole of 2-methylpropan-2-ol from Ethylethanoate equivalents of CH$$_3$$MgBr reagent will be required. (Integer value)

The target molecule is 2-methylpropan-2-ol, which is (CH₃)₃COH — a tertiary alcohol.

The starting material is ethyl ethanoate (ethyl acetate): CH₃COOC₂H₅.

The Grignard reagent is CH₃MgBr (methylmagnesium bromide).

In the first step, CH₃MgBr attacks the carbonyl carbon of ethyl ethanoate. One equivalent of Grignard adds to give a tetrahedral intermediate (a magnesium alkoxide): CH₃-C(CH₃)(OMgBr)-OC₂H₅. This intermediate is a hemiketal-like species that collapses: the ethoxide (C₂H₅O⁻) is expelled as a leaving group, generating a ketone intermediate — in this case acetone (propan-2-one): CH₃COCH₃.

In the second step, a second equivalent of CH₃MgBr adds to the acetone formed. The Grignard adds to the carbonyl of acetone to give the magnesium alkoxide: (CH₃)₃COMgBr. Aqueous workup gives the tertiary alcohol: (CH₃)₃COH = 2-methylpropan-2-ol.

Thus, 2 equivalents of CH₃MgBr are required in total: 1 equivalent to react with ethyl ethanoate to produce acetone, and 1 equivalent to add to the acetone to give 2-methylpropan-2-ol.

Therefore, the answer is $$\boxed{2}$$ equivalents.