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A number is totally even if all its digits are even for instance the number 2022 is totally even.
How many four-digit totally even numbers X are there such that X+2022 is also totally even?
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The units digit of our number should be and can be any of 0, 2, 4, 6 (four opportunities).
The tens digit of our number should be and can be any of 0, 2, 4, 6 (four opportunities).
The hundreds digit of our number should be and can be any of 0, 2, 4, 6, 8 (five opportunities).
The thousands digit of our number should be and can be any of 2, 4, 6 (three opportunities).
So, there are 4*4*5*3 = 16*15 = 240 such 4-digits totally even numbers, satisfying the condition. ANSWER
Solved.
