 Hong Kong
Stage 2

# Add and subtract large numbers II

Lesson

After seeing the standard algorithm for adding and subtracting large numbers, you might also want to see some other options.

You may find it easier to do certain addition and subtraction problems if you regroup the numbers first. Watch the video below to see how regrouping can be applied to larger addition and subtraction problems.  Then, try some of the worked examples below.

Remember!
• You can trade a number for another equal amount.  (This is called substitution.)

#### Worked Examples

##### question 1

Evaluate $10400+10600$10400+10600 by doing the following.

1. Fill in the box with the missing number.

$10400=10000+\editable{}$10400=10000+

2. Fill in the box with the missing number.

$10600=\editable{}+600$10600=+600

3. Using the results from the previous parts, evaluate $10400+10600$10400+10600.

##### question 2

Partition numbers  to evaluate $14010+26090$14010+26090.

##### question 3

Using regrouping, evaluate $100000-2000$1000002000.