Resposta:

Explicação passo a passo:

{647+[320-(6.3-18.4)].46}

{647+[320-(18-18.4)].46}

{647+[320-(18-72)].46}

{647+[320-(-54)].46}

{647+[320+54].46}

{647+[374].46}

{647+17.204}

17.851