Page 39 - Fun with Mathematics 2

SUBTRACTION ACROSS ZEROS

Very often, we make mistakes with zeros. So, let us practice subtraction

across zeros.

Hint: Not enough ones to subtract. There are no tens.
Th H T O
9
1 10 15 Let’s go to the hundreds. 1 hundred becomes 10 tens.
1 2 0 5 Now, 1 ten becomes 10 ones.
– 1 8 7 10 ones + 5 ones = 15 ones – 7 ones = 8 ones

1 0 1 8 Now, it is simple.

The difference between 1205 and 187 is 1018.

CHECKING YOUR SUBTRACTION

If you add the difference to the smaller number, you will get the greater number.

Th H T O Th H T O
1
1
10
7 10
Greater number 5 8 1 0 Checking: Difference 2 2 2 1
Smaller number – 3 5 8 9 Smaller number + 3 5 8 9
Difference 2 2 2 1 Greater number 5 8 1 0

FINDING THE MISSING NUMBERS

(a) To find the greater of the missing numbers, add the difference to the
smaller number—just as you did to check your subtraction problem.

Example: Stamps in a box Gave to friend Now I have

? – 785 = 216

How many stamps were there in the box?

(Add the difference to 2 1 6 Difference

what was subtracted) + 7 8 5 Smaller number

1 0 0 1 Greater number

(b) To find the smaller of the missing numbers, subtract the difference from
the greater number.

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