Page 37 - Start Up Mathematics_3

TTh Th H T O

1 8 2 5 4 Step 5: 16 is a 2-digit number. Write 6 in the
+ 7 9 1 8 thousands place and carry over 1 to
the ten thousands place. As there is
1 6 1 7 2 no number in the ten thousands

So, 8254 + 7918 = 16172. place, keep the 1 carried over.

Common Mistake!
Th H T O
1 1
6 3 4 7
Always remember + 1 8 5 9 Mental Maths
to add the carried
over digit. 8 1 9 6
What will be 7400
Carry over is not added added to 3150?

Addition of Three 4-Digit Numbers

We add three 4-digit numbers in the same way as we add two 4-digit numbers.

Example 3: Add 4913, 5062 and 7428.

Solution: TTh Th H T O
1 1 4 1 9 1 1 3 Mental Maths

5 0 6 2
300 + 2000 + 4500 = ?
+ 7 4 2 8

1 7 4 0 3

So, 4913 + 5062 + 7428 = 17403.

Addition Facts

Let’s revise the addition facts by taking bigger numbers.

1. Two or more numbers can be added in any order.
For example, 7460 + 3321 = 10781

and 3321 + 7460 = 10781

2. Adding ‘0’ to a number gives the same number.

For example, 3891 + 0 = 3891
and 0 + 7243 = 7243

29