Number Sequence to 20

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Answer Key & Explanations

Number Sequence to 20 · Kindergarten · Worksheet 2

1. Look at the pattern: ★ ★ ★ ★ | ★ ★ ★ ★ | ★ ★. How many stars are there in total? Answer: 10 Solution: Count the stars in the first group: ★ ★ ★ ★ = 4 stars Count the stars in the second group: ★ ★ ★ ★ = 4 stars Count the stars in the third group: ★ ★ = 2 stars Add all the stars together: 4 + 4 + 2 = 10 The answer is 10.
   Full step-by-step solution

   Step 1: Count the stars in the first group: ★ ★ ★ ★ = 4 stars Step 2: Count the stars in the second group: ★ ★ ★ ★ = 4 stars Step 3: Count the stars in the third group: ★ ★ = 2 stars Step 4: Add all the stars together: 4 + 4 + 2 = 10 The answer is 10.

2. Kaia sees a number line on the wall. The numbers go: 13, 14, ____. What is the missing number? Answer: 15 Solution: Look at the two numbers we know: 13 and 14. The numbers go up by 1 each time. From 13 to 14 is +1.
   Full step-by-step solution

   Step 1: Look at the two numbers we know: 13 and 14. Step 2: The numbers go up by 1 each time. From 13 to 14 is +1. Step 3: So the missing number must be 14 + 1 = 15. The answer is 15.

3. Sarah is hopping along a path of numbered stones. The stones Sarah hops on say: 11, 12, ___. What number is on the missing stone? Answer: 13 Solution: See the numbers on the stones Sarah hopped on: 11 and 12. The numbers go in order, increasing by 1 each time: 11 to 12 is +1. The missing stone comes after 12, so it is 12 + 1 = 13.
   Full step-by-step solution

   Step 1: See the numbers on the stones Sarah hopped on: 11 and 12. Step 2: The numbers go in order, increasing by 1 each time: 11 to 12 is +1. Step 3: The missing stone comes after 12, so it is 12 + 1 = 13. The answer is 13.

4. Look at the pattern: 🟥 🟥 🟥 | 🟥 🟥 🟥 | 🟥 🟥 🟥. How many red squares are there in total? Answer: 9 Solution: Identify the groups. The vertical bars "|" separate the squares into groups. - First group: 🟥 🟥 🟥 → 3 red squares - Second group: 🟥 🟥 🟥 → 3 red squares - Third group: 🟥 🟥 🟥 → 3 red squares Add the number of squares in each group.
   Full step-by-step solution

   Let's break down the problem step by step. We see the pattern: 🟥 🟥 🟥 | 🟥 🟥 🟥 | 🟥 🟥 🟥 Step 1: Identify the groups. The vertical bars "|" separate the squares into groups. - First group: 🟥 🟥 🟥 → 3 red squares - Second group: 🟥 🟥 🟥 → 3 red squares - Third group: 🟥 🟥 🟥 → 3 red squares Step 2: Add the number of squares in each group. 3 + 3 + 3 = 9 Step 3: Verify by counting all squares without grouping. If we ignore the bars, there are 9 red squares in a row: 🟥 🟥 🟥 🟥 🟥 🟥 🟥 🟥 🟥. Counting them one by one also gives 9. Step 4: Conclusion. The total number of red squares is 9.

5. Lily has 4 red crayons. Her friend Noah gives her 3 blue crayons. How many crayons does Lily have now? Answer: 7 Solution: Lily starts with 4 red crayons. Noah gives her 3 blue crayons. To find the total number of crayons, add the red crayons and the blue crayons together.
   Full step-by-step solution

   Step 1: Lily starts with 4 red crayons. Step 2: Noah gives her 3 blue crayons. Step 3: To find the total number of crayons, add the red crayons and the blue crayons together. Step 4: 4 + 3 = 7 Step 5: So, Lily now has 7 crayons in total.

6. 12, 13, _, 15 Answer: 14 Solution: Look at the sequence: 12, 13, _, 15 Notice that 12 comes before 13, so the numbers are increasing 13 is one more than 12, so the pattern is counting up by ones After 13 comes 14, then 15 The missing number is 14 The answer is 14.
   Full step-by-step solution

   Step 1: Look at the sequence: 12, 13, _, 15 Step 2: Notice that 12 comes before 13, so the numbers are increasing Step 3: 13 is one more than 12, so the pattern is counting up by ones Step 4: After 13 comes 14, then 15 Step 5: The missing number is 14 The answer is 14.

7. What number comes after 3? Answer: 4 Solution: When counting up, the number after 3 is 4.
8. Noah is hopping along a path of numbered stones. The stones Noah hops on say: 12, 13, ___. What number is on the missing stone? Answer: 14 Solution: See the numbers on the stones Noah hopped on: 12 and 13. The numbers go in order, increasing by 1 each time: 12 to 13 is +1. The missing stone comes after 13, so it is 13 + 1 = 14.
   Full step-by-step solution

   Step 1: See the numbers on the stones Noah hopped on: 12 and 13. Step 2: The numbers go in order, increasing by 1 each time: 12 to 13 is +1. Step 3: The missing stone comes after 13, so it is 13 + 1 = 14. The answer is 14.

9. What number comes after 8? Answer: 9 Solution: When counting up, the number after 8 is 9.
10. Lily has 4 red balloons. Her friend gives her 3 blue balloons. How many balloons does Lily have now? Answer: 7 Solution: Lily starts with 4 red balloons. Her friend gives her 3 blue balloons. To find the total number of balloons, add the red balloons and the blue balloons together: 4 + 3 = 7 So, Lily now has 7 balloons in total.
    Full step-by-step solution

    Step 1: Lily starts with 4 red balloons. Step 2: Her friend gives her 3 blue balloons. Step 3: To find the total number of balloons, add the red balloons and the blue balloons together: 4 + 3 = 7 Step 4: So, Lily now has 7 balloons in total.