Question

Верно ли утверждение? количество трёхзначных чисел, у которых первая и последняя цифры одинаковые, равно 90?

Answer 1

Да. 101,111,121,131,141,151,161,171,181,191,202,212,

222,232,242,252,262,272,282,292,

303,313,323,333,343,353,363,373,

383,393,404,414,424,434,444,454,

464,474,484,494,505,515,525,535,

545,555,565,575,585,595,606,616,

626,636,646,656,666,676,686,696,

707,717,727,737,747,757,767,777,

787,797,808,818,828,838,848,858,

868,878,888,898,909,919,929,

939,949,959,969,979,989,999