Answer:
6.38
Step-by-step explanation:
line up the decimals
it helps to add another 0 to 2.6 so that you can align them better
1
2.60
+ 3.78
= 6.38
8 + 0 = 8
6 + 7 = 13; write 3 and carry the one over above the 2 in 2.60
2 + 3 + 1 = 6
I tried my best to show it through text.