Observe the pattern and complete it.
15873×7×1=111111
15873×7×2=222222
15873×7×3=333333
15873×7×.....=444444
15873×7×5=...................×7×6=666666
Step 1; Observing the pattern, we conclude that
15873×7×4=444444
15873×7×5=555555
15873×7×6=666666
Complete the pattern:
1+3=2×21+3+5+7=4×41+3+5+7+9+11=