diff --git a/src/dice.c b/src/dice.c
new file mode 100644
index 0000000..50acdf4
--- /dev/null
+++ b/src/dice.c
@@ -0,0 +1,44 @@
+#include "dice.h"
+#include <stdlib.h>
+#include <memory.h>
+
+int roll_die(enum die_type die) {
+	int const max = die - 1;
+	return (rand() % max) + 1;
+}
+
+static int current_active_count = 0;
+static enum die_type active_dice_set[MAX_ACTIVE_DICE];
+
+enum die_type const *get_active_dice_set(size_t *out_length) {
+	if (out_length != nullptr) {
+		*out_length = current_active_count;
+	}
+	return active_dice_set;
+}
+
+size_t add_die_to_active(enum die_type die) {
+	if (current_active_count >= MAX_ACTIVE_DICE) {
+		return MAX_ACTIVE_DICE;
+	}
+	active_dice_set[current_active_count] = die;
+	return current_active_count++;
+}
+
+void remove_die_from_active(size_t index) {
+	memmove(active_dice_set + index + 1, active_dice_set + index, MAX_ACTIVE_DICE - index - 1);
+}
+
+struct roll_result_type roll_active_dice_set(enum die_type die) {
+	struct roll_result_type results = {
+		.individual_result_count = MAX_ACTIVE_DICE,
+		.total = 0
+	};
+	for (size_t i = 0; i < current_active_count; ++i) {
+		results.individual_results[i] = roll_die(active_dice_set[i]);
+		results.total += results.individual_results[i];
+	}
+
+	return results;
+}
+
diff --git a/src/dice.h b/src/dice.h
new file mode 100644
index 0000000..370edac
--- /dev/null
+++ b/src/dice.h
@@ -0,0 +1,33 @@
+#ifndef DICE_H
+#define DICE_H
+
+#include <stdlib.h>
+
+#ifndef MAX_ACTIVE_DICE
+#define MAX_ACTIVE_DICE 5
+#endif
+
+enum die_type {
+	COIN = 2,
+	D4 = 4,
+	D8 = 8,
+	D10 = 10,
+	D12 = 12,
+	D20 = 20,
+	D100 = 100
+};
+
+struct roll_result_type {
+	size_t individual_result_count;
+	int individual_results[MAX_ACTIVE_DICE];
+	int total;
+};
+
+extern int roll_die(enum die_type die);
+
+extern enum die_type const *get_active_dice_set(size_t *out_length);
+extern size_t add_die_to_active(enum die_type die);
+extern void remove_die_from_active(size_t index);
+extern struct roll_result_type roll_active_dice_set(enum die_type die);
+
+#endif // !DICE_H