Найдите последнюю цифру:
а) 1999 * 1999 * 1999 * 1999 * 1999 * 1999 * 1999;
б) $2009^5$;
в) $9999^{10}$.
1999 * 1999 * 1999 * 1999 * 1999 * 1999 * 1999 = ...9 * ...9 * ...9 * ...9 * ...9 * ...9 * ...9 = ...1 * ...1 * ...1 * ...9 = ...9
Ответ: 9
$2009^5 = ...9 * ...9 * ...9 * ...9 * ...9 = ...1 * ...1 * ...9 = ...9$
Ответ: 9
$9999^{10} = ...9 * ...9 * ...9 * ...9 * ...9 * ...9 * ...9 * ...9 * ...9 * ...9 = ...1 * ...1 * ...1 * ...1 * ...1 * ...1 * ...1 * ...1 * ...1 * ...1 = ...1$
Ответ: 1