10(6)+1=61
10(15)+3=153
10(4)+7=47
10(9)+9=99
this is true because when you multiply a number by 10 it will be an even number(2,4,6,8,etc...)...then when you add an odd number to that the number will turn odd(153,47,99,etc..)... and when you multiple integers they will always multiply to an even number
