Addition

Addition
1. Adding in your head

For simple numbers, you can try to add them in your head.
You can make it easier by:

Breaking up numbers
40 + 67 is the same as
40 + 60 + 7, which is
107
Rounding numbers
42 + 89 is the same as
(40 + 80) + (2 + 9), which is
120 + 11, which is
131
Remember, you can always jot down numbers on paper while you are adding in your head.

Addition
1. Adding in your head

For simple numbers, you can try to add them in your head.
You can make it easier by:

Breaking up numbers
40 + 67 is the same as
40 + 60 + 7, which is
107
Rounding numbers
42 + 89 is the same as
(40 + 80) + (2 + 9), which is
120 + 11, which is
131
Remember, you can always jot down numbers on paper while you are adding in your head.

2. Writing it down

7948 + 1223 =

If the numbers are too high or too difficult to add in your head,
write them down in columns. Separate the numbers into units, tens,
hundreds and thousands. Always start adding with the units first.

3. Useful tips
Estimate first and check afterwards. It's a good idea to estimate a rough answer first. And always check your actual answer.
Order doesn't matter. 394 + 88 is the same as 88 + 394
Key words. Look out for these words in problems: total, sum, altogether, more. They all indicate an addition calculation.

QUIZ

1. Which two numbers add up to make 100?
38 and 52
53 and 47
22 and 77
2. What is the sum of 200, 300, 150 and 250?
900
850
1000
3. What is the missing number? 87 + ? = 130
35
50
43
4. What do you get if you increase 316 by 500?
616
800
816
5. What answer do you get if you add 436 to 523?
959
795
946
6. What must be added to 378 to make 400?
33
22
44
7. What could you add to 3.7 to make 4?
0.2
0.3
1.3
8. What can you add to 7.44 to make 8?
0.56
1.56
0.46
9. Which of these gives the biggest answer?
40 + 7
30 + 11
20 + 23
10. Which is higher?
7645 + 3757
3757 + 7645
They're both the same