3 What is different about the subtraction 686 − 339? Look at what we need to do so we can subtract 9 ones.
H T O 6 8 6 − 3 3 9 3 4 7 7 1
H
T O
16 ones − 9 ones = 7 ones 7 tens − 3 tens = 4 tens 6 hundreds − 3 hundreds = 3 hundreds
(a) Estimate the answer to 594 − 427. 594 rounds to
1
to the nearest 100
427
?
594
to the nearest 100
427 rounds to
−
=
(b) Complete the calculation using the two different methods. 594 − 427 =
H T O 5 9 4
−
=
−
=
− 4
2
7
−
=
+
+
=
44
9781380050694__text.indb 44
04/05/2022 15:49
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