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Regrouping Hundreds to Tens

If there are not enough tens in minuend, we regroup 1 hundred to 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 abacus for doing
mathematical calculation. Nowadays, a calculator is used 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 hundreds and tens, that 1 13
is, borrow 1 hundred to tens. 2 3 9
So, 2 hundreds 3 tens = 1 hundred – 1 7 3
13 tens 6 6
Now, 13 tens – 7 tens = 6 tens

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

Thus, 239 – 173 = 66 – 1 7 3
0 6 6

teacher’s
tip Discuss with children with examples, that opposite to addition, maintaining the order is very important in
subtraction. We cannot change the minuend with subtrahend.

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