Page 37 - Math Genius C3

E:\Working\Orange_Education\Math_Genius_3\Open_Files\CHAP_02
\ 01-Oct-2025 Bharat Arora Proof-10 Reader’s Sign _______________________ Date __________

Addition of three 3-digit numbers

Adding three 3-digit numbers is the same as adding two 3-digit numbers.

Let us add 217 + 342 + 153. Arrange the numbers in the place value columns and follow

the given steps:
Step 1: Add the ones. H t O

7 + 2 + 3 = 12 ones = 1 ten + 2 ones. 1 1

Write 2 in the ones column and carry over 1 ten to the tens 2 1 7
column. 3 4 2
Step 2: Add the tens. + 1 5 3

1 (carried over) + 1 + 4 + 5 = 11 tens = 1 hundred + 1 ten. 7 1 2

Write 1 in the tens column and carry over 1 hundred to the
hundreds column.

Step 3: Add the hundreds.
1 (carried over) + 2 + 3 + 1 = 7 hundreds.

Write 7 in the hundreds column.

Thus, 217 + 342 + 153 = 712.

Think Tank Logical Thinking

Find the missing numbers in the addition pyramid. 182
Hint: Each block (except the bottom row) has the sum of the 48
two numbers below it. 20 26 22 18

practice time 2B

1. Add the following. Identify which place values need regrouping.

(a) H t O (b) H t O (c) H t O

7 0 9 5 2 3 7 8 5
+ 1 0 4 + 1 8 3 + 1 1 5

2. Find the sum of the following.

(a) H t O (b) H t O (c) H t O

2 4 7 5 4 9 3 5 8
+ 3 3 5 + 3 6 4 + 2 7 0

Mathematics-3 35