Unit 3 – Addition and subtraction
3 What is different about the addition 365 + 138? Look at what happens when the 5 ones and 8 ones are added.
We start by adding the ones: 5 ones + 8 ones = 13 ones 6 tens + 3 tens = 9 tens 3 hundreds + 1 hundred = 4 hundreds +
We can regroup to make another ten, so 13 ones is 1 ten and 3 ones.
H T O 3 5 5 + 1 3 8 4 9 3 1
(a) Estimate the answer to 678 + 217. 678 rounds to
1
to the nearest 100
678
217
?
to the nearest 100
217 rounds to
+
=
(b) Complete the calculation using the two different methods. 678 + 217 = 600 + + + + +
=
+
+
H T O 6 7 8
=
+
+ 2
1
7
=
41
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04/05/2022 15:49
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