Global Numbers Error

[Sierra King]

Recieve This error when putting in the query below: "Msg 245, Level 16, State 1, Line 63
Conversion failed when converting the nvarchar value 'z' to data type int."

Select SUM(new_cases) as total_cases, SUM(cast(new_deaths as int)) as total_deaths, SUM(cast(new_deaths as int))/SUM(New_Cases)*100 as DeathPercentage
From [Portfolio Project]..CovidDeaths
--Where location like '%states%'
where continent is not null
--Group By date
order by 1,2

[Ikhlas Ahmad]

Try using this query,
Select SUM(new_cases) as total_cases, SUM(CONVERT(int, new_deaths)) as total_deaths, (SUM(CONVERT(int, new_deaths))/SUM(new_cases))*100 as DeathPercentage
From CovidDeaths
Where continent is not null

it works for me.