a) 10700-9800=900
9800,10700,11600,12500
b) 10400:2=5200
5200:2=2600
2600,5200,10400,20800,41600,83200
c) 500005, 40004, 3003, 202,10
d) 302000,301000,300000,299000,298000,297000,296000
e) 123456,234561,345612,456123,561234,612345
f) 400,500,900,1400,2300,3700,6000,9700