1.？ 246 +? 358? =? 604

In this formula, the single digits add up to get 14, which has been carried, and then the ten digits add up to get 10, which needs to be carried to the hundred digits, and the hundred digits add up to get? 6. What's the final total? 604, meet the requirements of continuous carry.

2.？ 579? +? 690? =? 1269

How many digits are added up in this formula? Add 9 and 10 digits to get it? 16, which needs to be rounded to the nearest hundred. What's the total? 12, also need to carry, what is the final sum? 1269, which also meets the requirements of continuous carry.

Similarly: 156+264 = 420, 458+667 =125, 109+495 = 604, 562+ 147 = 709.