Page 36 - Start Up Mathematics_4

14 is a 2-digit number. Keep the 4 ones and carry over the 1 ten.

So, we write 8 in the blank space. TTh Th H T O
Step 3: Add the hundreds including the 1 1 1
carried over. 1 ? 3 8 4

1 + 3 + 2 = 6 + ? 6 2 5 7
So, we write 6 in the blank space. 6 8 6 4 1
Step 4: Look at the thousands column.

? + 6 = 8 TTh Th H T O

8 is more than 6. 1 2 1 3 1 8 4
Also, sum – one addend = other addend + ? 6 2 5 7

? = 8 – 6 = 2 6 8 6 4 1

So, we write 2 in the blank space.
Step 5: Look at the ten thousands column.
TTh Th H T O
1 + ? = 6 1 2 1 3 1 8 4
6 is more than 1.
+ 5 6 2 5 7
? = 6 – 1 = 5 6 8 6 4 1

So, we write 5 in the blank space.

Example 8: Find the missing digits.
L TTh Th H T O

5 ? 3 2 6 ?

? 5 ? 3 ? 3

+ 2 0 2 ? 0 0

8 8 9 8 8 9

Solution: L TTh Th H T O
5 3 3 2 6 6

1 5 4 3 2 3

+ 2 0 2 3 0 0

8 8 9 8 8 9

Estimating the Sum

Estimation gives a rough (or approximate) value of the sum. We can round off a number to
any place depending upon the degree of accuracy required.

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