$sqrt

Update records by setting the value of a numeric column to the square root of its current value. The $sqrt method is used to modify numeric fields by applying the square root operation, which is useful in cases where you want to transform data, like calculating the square root of a number stored in the column.

await Member.$update({
    $where: { 
        age: { 
            $eq: 16 
        } 
    },
    $update: {
        $sqrt: {
          age: 2
        }
    }
});