Page 54 - Math Genius C3

E:\Working\Orange_Education\Math_Genius_3\Open_Files\CHAP_03
\ 01-Oct-2025 Bharat Arora Proof-10 Reader’s Sign _______________________ Date __________

Regrouping Hundreds to Tens

If there are not enough tens in the minuend, we regroup 1 hundred into 10 tens.

For example:

H t O
1 12

2 hundreds 2 tens 1 hundred 12 tens 2 2 0

Knowledge Desk

In ancient times, people used bones, pebbles and later abacuses for Cross-Curricular Learning
mathematical calculations. Nowadays, we use a calculator for calculation. It is a
device used for making mathematical calculations faster.

Example 2: Subtract 173 from 239.
Solution: Write the numbers in columns and follow the given steps:

Step 1: Subtract the ones. H t O

9 ones – 3 ones 2 3 9
= 6 ones – 1 7 3
6

Step 2: Subtract the tens.
7 tens cannot be subtracted from
3 tens. H t O
So, regroup the hundreds and tens, 1 13

that is, borrow 1 hundred to tens. 2 3 9
So, 2 hundreds 3 tens = 1 hundred – 1 7 3
and 13 tens 6 6
Now, 13 tens – 7 tens = 6 tens

Step 3: Subtract the hundreds.
1 hundred – 1 hundred H t O
1 13
= 0 hundreds 2 3 9

Thus, 239 – 173 = 66 – 1 7 3
0 6 6

Teacher’s Discuss with students with examples, that unlike addition, maintaining the order is very important in
Tip subtraction. We cannot interchange the minuend and subtrahend.

52 Mathematics-3