Answer:
823
<u>Method 1</u>
Break the three numbers into hundreds, tens and units, then add these separately (starting with the units)
197 = 1 hundred, 9 tens, 7 units
203 = 2 hundreds, 0 tens, 3 units
423 = 4 hundreds, 2 tens, 3 units
Units: 7 + 3 + 3 = 13
Tens: 9 + 2 = 11 tens = 110
Hundreds: 1 + 2 + 4 = 7 hundreds = 700
Add these together: 700 + 110 + 13 = 823
<u>Method 2</u>
First add 203 to 197:
Borrow the 3 from 203 and add it to 197: 197 + 3 = 200
Add the remaining 200: 200 + 200 = 400
Now add 423 to 400: 400 + 423 = 823
⇒ 203 + 197 + 423 = (203 + 197) + 423
= 400 + 423
= 823
