Hey, sorry this is a noob question, but can anyone refresh me about the divide-by-9 trick? I'm having trouble breaking 110 without this.
7899/9 = add up four numbers (7899), 33, divide by 9, 3 2/3, write 2/3 as the remainder, remember the 3 add up three numbers (789)+3, 27, write 7, remember 2 add up two numbers (78)+2, 17, write 7, remember 1 add up one number (7)+1, 8, write 8 answer is 877 2/3
999/9 = add up three numbers (999), 27, divide by 9, 3, write nothing as the remainder, remember 3 add up two numbers (99)+3, 21, write 1, remember 2 add up one number (9)+2, 11, write 1, remember 1 write 1 answer is 111
