Math New Drill : Level 1 SNJ00-0801-L1 Integers not expressed by the combination of 5 or 6

How many prices of more than or equal to one yen which can not expressed by the combination of 5 yen stamp and 6 yen stamp only?













Answer
10 prices

Solution
It's put in order using a table below.
Green number can be expressed, but red can't be expressed.
Therefore altogether, 4 + 3 + 2 + 1 = 10 ways.