
Written solutions to the chapter problems. Check each step, then correct yourself.
1 Count and add ★★★
There are 2 orange counters and 3 blue counters. Put them together and count: 1, 2, 3, 4, 5.
\(2 + 3 = 5\)
There are 5 counters in all.
2 Fingers ★★★
We put the fingers together: \(4 + 1 = 5\).
Sam shows 5 fingers.
3 Doubles ★★★
- \(1 + 1 = 2\)
- \(2 + 2 = 4\)
- \(3 + 3 = 6\)
Adding the same number twice is called a double.
4 Birds on a branch ★★★
This is an adding-to story. We start with 4 and 2 more come.
\(4 + 2 = 6\)
There are 6 birds on the fence.
5 Hop on the number line ★★★
From 3, hop: 4, 5, 6. You land on 6.
\(3 + 3 = 6\)
6 Ten frame story ★★★
The first row has 5 orange counters. The second row has 2 blue counters.
\(5 + 2 = 7\)
The sum is 7.
7 Adding zero ★★★
- \(6 + 0 = 6\)
- \(0 + 4 = 4\)
When you add 0, the number does not change, because you add nothing.
8 How many empty spaces? ★★★
There are 6 orange counters and 3 blue counters: \(6 + 3 = 9\).
The frame has 10 spaces and 9 are full. So 1 space is empty.
9 True or false? ★★★
- True. Hopping 4 from 3 lands on 7.
- False. \(5 + 2 = 7\), not 8.
- True. Adding 1 gives the next number after 6, which is 7.
10 Switch the order ★★★
\(2 + 6 = 8\) and \(6 + 2 = 8\).
The sums are the same. The order of the addends does not change the sum.
11 Cookies on a plate ★★★
We start with 5 and add 4 more: \(5 + 4 = 9\).
There are 9 cookies on the plate.
12 Draw the story ★★★
Draw 3 circles, then 4 more circles, and count them all.
\(3 + 4 = 7\). Maya has 7 stickers.
13 Ways to make 7 ★★★
Here are all the pairs, starting from 0: \(0 + 7\), \(1 + 6\), \(2 + 5\), \(3 + 4\). Switching the order gives more pairs, such as \(6 + 1\).
Any three of these are correct, and each one has the sum 7.
14 Which sum is bigger? ★★★
\(4 + 3 = 7\) and \(2 + 4 = 6\).
Since 7 is bigger than 6, \(4 + 3\) is bigger.
15 Make 10 ★★★
The frame has 4 empty spaces. Filling them with 4 blue counters makes 10.
\(6 + 4 = 10\). You need 4 blue counters.
16 Three teams ★★★
First add two numbers: \(2 + 3 = 5\). Then add the last team: \(5 + 4 = 9\).
\(2 + 3 + 4 = 9\). The teams score 9 points in all.
17 Act it out ★★★
Put 5 counters in a box that is the bus. Then put 3 more counters in the box. Count all the counters: 8.
\(5 + 3 = 8\). There are 8 children on the bus.
18 Find the mistake ★★★
Start at 4 on a number line and hop 5 times: 5, 6, 7, 8, 9. You land on 9.
\(4 + 5 = 9\). Leo is not right. He stopped one hop too early.
19 Match the story ★★★
The plus sign means joining, so we need a story where ducks come.
The answer is (a). In story (b) the ducks leave, so the group gets smaller.
20 Write your own story ★★★
Example: Noah has 3 toy trucks. He gets 6 more toy trucks for his birthday. How many trucks does he have?
\(3 + 6 = 9\). Noah has 9 trucks. (Many other stories are correct.)
21 Mystery numbers ★★★
Try pairs that make 9: \(1 + 8\), \(2 + 7\), \(3 + 6\), \(4 + 5\).
Only \(4 + 5\) has numbers that differ by 1. The numbers are 4 and 5.
22 Two hops ★★★
From 1, hop 2: you land on 3. Then hop 3 more: 4, 5, 6.
\(1 + 2 + 3 = 6\). You land on 6.
Test yourself: quick challenge for Kindergarten
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