Answer:
18
Step-by-step explanation:
Write double you used. is twice of what I used so
8+10=18
or
4+4+5+5=18
or 4+5=9*2=18
Hey there!
4 + 5 = 9
I am not really sure what you mean by "write double you used", but if you wanted the double of 9, it would be 18.
Hope this helps!
Have a great day!
