10a-3a+5a=( )
12
12a
算一算，选一选5c-4c=( )
c
1
算一算，选一选5x+16x=( )
21x
21x×x
算一算，选一选y+9y=( )
9y×y
10y
算一算，选一选4b-2b=( )
2b
2
算一算，选一选3m+5m=( )
15
8m
算一算，选一选12n+n=( )
13n×n
13n
算一算，选一选4x+x=( )
5
5x