Question

Em quantos números de 0 a 999 aparece o algarismo 9? Metodologia por favor!

Answer 1

São os número: 9,19,29,39,49,59,69,79,89,90,91,92,93,94,95,96,97,98,99,109,119,129,139,149,159,169,179,189,190,191,192,193,194,195,196,197,198,199,209,219,229,239,249,259,269,279,289,290,291,292,293,294,295,296,297,298,299,309,319,329,339,349,359,369,379,389,390,391,392,393,394,395,396,397,398,399,409,419,429,439,449,459,469,479,489,490,...,499,509,519,529,539,549,559,569,579,589,590,...,599,609,619,629,639,649,659,669,679,689,690,...,699,709,719,729,739,749,759,769,779,789,790,...,799,809,819,829,839,849,859,869,879,889,890,...,899,900,...,909,...,,919,929,939,949,959,969,979,989,990,...,999.
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no total aparecem : 271