Add Whole Numbers and Money

We can use models to add numbers with regrouping

Step 1: Add ones. If the sum is greater than 10, regroup. 10 ones = 1 tens
Step 2: Add tens. If the sum is greater than 10, regroup. 10 tens = 1 hundreds
Step 3: Add hundreds. If the sum is greater than 10, regroup. 10 hundreds = 1 thousands. Similarly add thousands

When the numbers are close to a ten or hundred you can use compensation method to simplify addition

If we add a number to one addend and subtract the same number from the other addend, the sum remains the same. For example – To add 29 and 31, add 1 to 29 to make it 30 and subtract 1 from 31. The sum of 29 and 31 is 30 + 30 = 60

Column method and Zigzag method can be used to add numbers

To add using the column method, first draw lines to separate the ones, tens, and hundreds places and write each sum in its column

If there are 2 digits in the ones place, trade 10 ones for 1 ten. If there are 2 digits in the tens place, trade 10 tens for 1 hundred

To add using the Zigzag method, first round the number to be added to its nearest hundred. Add the nearest hundred to other number

Next round the number to be added to its nearest ten. Add the nearest ten to the number. Then add the ones