Lets look a pyramid numbers
we have
1st=1
2nd=2
3rd=6
we notice that we jsut add the previous number on
so 1st=1
2nd=1+1
3rd=1+2+3
4th=1+2+3+4
so therefor to get from 100th to 101th, just add 101
Answer:
9
Step-by-step explanation:
total is 30
spent is $9
this is total money minus the amount of the picture frame
30-9
21 divide by 3
the total sum of journals bought was 9