Dicey Operations Noah Al Sakat

Let's say you are chosen 4 random digits between 1 and 9. To get the sum close to 100, you use number bonds. If you have 5,7,3, and 4 as your numbers you choose 5 and 4 as your tens digits because 50+40 is closer to 100 than 50+30 or 50+70. Why don't we do 70+30? Because of the ones digits. The result we would  get from using 50+40 would give us 50+40+7+3=100 but using 70+30 would give us 70+30+5+4=109. If you have 2 digits that add to more than 5 but less than 16, you should try to get as close to 90 as possible with your remaining digits. If they add to 16 or above, aim for 80 with your 2 other digits. If they add to 5 or less, aim for 100 with your 2 remaining digits. 5+4=9 which is between 5 and 16. Therefore you should aim with 90 with your remaining digits, not 100.