
①15×15=225;25×25=625;35×35=1225;45×45=2025. ②1×1=1;11×11=121;111×111=12321,1111×1111=1234321;11111×11111=123454321. 故答案为:2025,123454321.

①15×15=225;25×25=625;35×35=1225;45×45=2025. ②1×1=1;11×11=121;111×111=12321,1111×1111=1234321;11111×11111=123454321. 故答案为:2025,123454321.