How to divide number into integer pieces that are each a multiple of n?

var number = 5000;
var n = 7;

var values = [];
while (number > 0 && n > 0) {
    var a = Math.floor(number / n / 50) * 50;
    number -= a;
    n--;
    values.push(a);
}  // 700 700 700 700 700 750 750

Edit

You can alternate Math.floor and Math.ceil to obtain the desired result:

while (number > 0 && n > 0) {
    if (a%2 == 0)
        a = Math.floor(number / n / 50) * 50;
    else
        a = Math.ceil(number / n / 50) * 50;
    number -= a;
    n--;
    values.push(a);
}  // 700 750 700 750 700 700 700

// i - an integer multiple of k
// k - an integer
// n - a valid array length
// returns an array of length n containing integer multiples of k
// such that the elements sum to i and the array is sorted,
// contains the minimum number of unique elements necessary to
// satisfy the first condition, the elements chosen are the
// closest together that satisfy the first condition.
function f(i, k, n) {
  var minNumber = (((i / k) / n) | 0) * k;
  var maxNumber = minNumber + k;
  var numMax = (i - (minNumber * n)) / k;
  var nums = [];
  for (var i = 0; i < n - numMax; ++i) {
    nums[i] = minNumber;
  }
  for (var i = n - numMax; i < n; ++i) {
    nums[i] = maxNumber;
  }
  return nums;
}

So your second example would be

f(5000, 50, 7)

which yields

[700,700,700,700,700,750,750]

Let a be your starting number, k - number of parts you want to divide to.
Suppose, that b = a/n.
Now you want to divide b into k close integer parts.

• Take k numbers, each equal to b/k (integer division).
• Add 1 to first b%k numbers.
• Multiply each number by n.

Example: a = 5000, n = 50, k = 7.
b = 100
Starting series {14, 14, 14, 14, 14, 14, 14}
Add 1 to first 2 integers {15, 15, 14, 14, 14, 14, 14}.
Multiply by 50 {750, 750, 700, 700, 700, 700, 700}.