Page 89 - Math Smart - 7

O Look at the table to see what happens when we divide a whole number
o
by 1000. Spotlight

1 ^ _ m
Addition and subtraction
1_ 8-^ _3-- 2 — •
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are inverse operations.
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Multiplication and
Fill in the blanks. division are inverse
operations.
a) When we divided 1832 by 1000, the digit moved from the
thousands column to the units column. Inverse operations are
b) When we divided 1832 by 1000, the digit 8 moved from the operations that undo
column to the column. each other.
Addition Subtraction
So when we divide a number by 1000, each digit moves one/two/
three* places to the left/right* in the place-value table. This makes a
number greater/smaller*.
Multiplication Division
*Circle the correct choice

Example 5

With measurements, we often work with decimals.
O Kyle has 432.1 m of rope. He needs to cut the rope into 10 equal pieces. How
long should each piece be? Give your answer in metres.

Divide 432.1 by 10. When you divide by 10, each digit moves one
place to the right. This makes the number smaller.
432.1 -r 10 = 43.21 metres

O Harry has 9192.3 kg of fish. He needs to serve 100 guests. How many grams of
fish are there in each serving?
Divide 9192.3 by 100. When you divide by 100, each digit moves two
9192.3 ^ 100 = 91.923 g places to the right. This makes the number smaller.

O Gale has run 3561.2 m. How many kilometres did Gale run?
Divide 3561.2 by 1000. When you divide by 1000, each digit moves
three places to the right. This makes the
3561.2-j-1000 = 3.5612 km
number smaller.

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