Fill in the blanks: 999+1 = _______
Observe the patterns and fill in the blanks:
116+9=116+10-1=115+10
116+99=116+100-1=115+100
116+999=116+1000-1=115+________________
116+9999=116+10000-1=115+_____________________
73×9=73×10-1=729
73×99=73×100-1=7299
73×999=73×1000-1=72999
73×9999=73×10000-1=______________________
73×99999=73×100000-1=____________________
Fill in the blanks:
1+(-1)=____