This is a numeric palindrome -- spelled (or in this case numbered) the same way forward and backward.
zero
1234567890 + 4563217890 = 5797785780
456789 * 1234567890 = 5.63937032 × 1014
The exponent of 1234567890 is 1 because anything to the 1st power equals that number.
The answer is 1.8253374e+18
2222222211
1,219,326,311,126,352,690
To round to the nearest 100, look at the 10s digit to decide whether to round up or down. The 10s digit of 6963 is 6 which is 5 or more, so round up: 6963 → 7000 to the nearest hundred.
1234567890
2469135780
zero
1.52415788 × 1018
1234567890 - 987654321 = 246913569
1234567890-1234567856 = 34
1 plus 1234567890 is 1234567891
1234567890+9876543210=11,111,111,100
1234567890 + 1098765432 = 2333333322