How a few batteries battery is calculated according to battery capacity

Single section 18650 lithium batteries generally 3.6 3.7 V, general is 2000-2400 mah capacity (new 18650 and 2600 mah, but high prices generally do not adopt) 3.6 * 3 = 10.8 can infer is 3 groups 3.6 V batteries in series, 2200 * 4 = 8800, can be concluded that the section is 4 2200 mah batteries and to a set of 3.7 V battery pack, then 3 * 4 = 12, the batteries are generally composed of 12 18650 lithium batteries.