let num1= '1'
let num2 = '1'
let arr1= Array.from(num1)
let arr2 = Array.from(num2 )
let mainArray = [...arr1, ...arr2 ]
let massiv_num = mainArray .map(i => Number(i))
// Итоговое значение
let sumOfNumbers = massiv_num.reduce((acc, number) => acc + number, 0);

родитель {
position: relative;
height: 100vh;
}
Дочерний{
position: absolute;
bottom: 0
}