Question

How many three-digit numbers are there, which have the last digit as the sum of the first two digits? For example, 358 has the last digit as the sum of the first two digits (3 + 5 = 8)

Answer 1

Answer :

we can write These type of three digit numbers As :

101 , 112 , 123 , 134 , 145, 156 , 167 , 178 , 189 = 9

202 , 213 , 224 , 235 , 246 , 257 , 268 , 279 = 8

303 , 314 , 325 , 336 , 347 , 358 , 369 = 7

404 , 415 , 426 , 437 , 448 , 459 = 6

505 , 516 , 527 , 538 , 549 = 5

606, 617 , 628 , 639 = 4

707, 718 , 729 = 3

808 , 819 = 2

909 = 1

SO, we can have these type of total numbers = 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 = 45 ( Ans )