Question

1. group the dots to help you count. circle dots to show your groups. a. how many dots are there in total? ________ b. describe another way you can group the dots.

Explanation:

Step1: Count rows and columns

There are 4 full - rows with 10 dots each and 2 extra dots.

Step2: Calculate total dots

The number of dots in 4 full - rows is $4\times10 = 40$, and adding 2 extra dots gives $40 + 2=42$.

Step3: Another grouping idea

We can think of it as 2 groups of 21 dots. We can split the rows in half (vertically) to get two groups where each group has 2 rows of 10 dots and 1 extra dot, so each group has $2\times10+1 = 21$ dots.

Answer:

a. 42
b. We can group the dots into 2 groups of 21 dots by splitting the array vertically.