End the match pattern with the number you are seeking, such as

  print "3-digits ending in 5" 
    if ( $number =~ m/\d{2}5$/ );
  print "4-digit number ending in 0 or 9"
    if ( $number =~ m/\d{3}[09]$/ );
  # as opposed to
  print "2 digits followed by a 3, but may have additional digits" 
    if ( $number =~ m/\d{2}3/ );
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Hope that helps.