Question

13. For how many three digit numbers (100 to 999) is the sum of the digits even? (For example, 343 has an even sum of digits: 3+4+3 = 10 which is even.) Find the answer and explain why it is correct in at least two different ways.

Answer 1

Carln't be in hundreds 5 even digits odd or give even Assuming the first digit, in hundreds place leading by o there are sodd, y even digits place. For tens place there can be 5 odd or and in unit place there can also five digits Now we get o u even 5 even 5 even =100 % u even 5 odd sodd .=100 : ①. 5 odd 5 odd seven = 125 Ø 50dd seven 5 odd =125 480 no. of three digits whose rum is even in 14.50] A