Subtracting Number From Neighbor 1

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
1-0=
2-1=
3-2=
4-3=
5-4=
6-5=
7-6=
8-7=
9-8=
10-9=
11-10=
12-11=
13-12=
14-13=
15-14=
16-15=
17-16=
18-17=