Answer:
49 leaves
Step-by-step explanation:
Given: Lisa collected 7 leaves each day and everyday for a week (7 days).
To find: The number of leaves collected by the end of the week.
Solution:
Total number of leaves collected in a day is 7.
Since there are 7 days in a week.
The leaves are collected for 7 days.
So, in order to find the total number of leaves collected we need to multiply 7 by 7.
the number of leaves collected by the end of the week 
Therefore, she collected 49 leaves by the end of the week.