99×99+199,
=(100-1)×99+199,
=9900-99+199,
=9900+100,
=10000,
=100×100;
结果为:(99+1) 2;
999×999+1999,
=(1000-1)×999+1999,
=999000-999+1999,
=999000+1000,
=1000000,
=1000×1000;
结果为:(999+1) 2;
由此得出规律:得数是算式中连续的数字9+1的和的平方数.
所以:99×99+199=100×100;
999×999+1999=1000×1000;
9999×9999+19999=(10000)×(10000).
故答案为:=;=;=,10000,10000.