Page 153 - NUMINO Challenge_K2
P. 153
Exploration
2. Add and Subtract
Unit Overview
Addition and subtraction are the most basic concepts in mathematics.
Students, who solve problems without a full understanding of operations, will
have trouble developing their mathematical thinking skills. Students must first
use objects to gain an understanding of addition and subtraction and then use
numbers and operation signs to improve their problem solving ability.
In this unit, guide the students to understand the meaning of addition and
subtraction through interpreting various situations into addition and
subtraction concepts and expressing the concepts in expressions. Guide the
students to experience the process of formalizing specific situations.
2. Add and Subtract
p.74 p.75
Addition Expressions Subtraction Expressions
Addition expressions have the following two meanings. Subtraction expressions have the following two meanings.
Expression 3 + 2 = 5 Read 3 added to 2 is 5. Expression 5 - 2 = 3 Read 2 subtracted from 5 is 3.
The sum of 3 and 2 is 5. The difference of 5 and 2 is 3.
2 goldfish were added to a bowl with 3 goldfish to make a There were 5 eggs. 2 were eaten, so there were 3 eggs left.
total of 5 goldfish.
In the bowl, there are 3 red goldfish and 2 yellow goldfish There are 5 eggs and 3 cookies, so there are 2 more eggs
that make a total of 5 goldfish. than cookies.
EExxeerrcciissee Write and read addition expressions. EExxeerrcciissee Write and read subtraction expressions.
2 +2=4 6 - 2= 4
2 2 4added to makes a total of . 6 2 4subtracted from is .
2 +4= 6 7 - 3= 4
2 4 6added to makes a total of . 7 3 4subtracted from is .
74 NUMINO Challenge K2 75Operations
Use terminologies that indicate addition or subtraction to familiarize students with the
vocabulary that they can use to determine if they should add or subtract. For example, add,
put together, all together, subtract, decreased by, and less than are some of the terms that are
used to indicate addition or subtraction.
24 NUMINO Challenge K2
2. Add and Subtract
Unit Overview
Addition and subtraction are the most basic concepts in mathematics.
Students, who solve problems without a full understanding of operations, will
have trouble developing their mathematical thinking skills. Students must first
use objects to gain an understanding of addition and subtraction and then use
numbers and operation signs to improve their problem solving ability.
In this unit, guide the students to understand the meaning of addition and
subtraction through interpreting various situations into addition and
subtraction concepts and expressing the concepts in expressions. Guide the
students to experience the process of formalizing specific situations.
2. Add and Subtract
p.74 p.75
Addition Expressions Subtraction Expressions
Addition expressions have the following two meanings. Subtraction expressions have the following two meanings.
Expression 3 + 2 = 5 Read 3 added to 2 is 5. Expression 5 - 2 = 3 Read 2 subtracted from 5 is 3.
The sum of 3 and 2 is 5. The difference of 5 and 2 is 3.
2 goldfish were added to a bowl with 3 goldfish to make a There were 5 eggs. 2 were eaten, so there were 3 eggs left.
total of 5 goldfish.
In the bowl, there are 3 red goldfish and 2 yellow goldfish There are 5 eggs and 3 cookies, so there are 2 more eggs
that make a total of 5 goldfish. than cookies.
EExxeerrcciissee Write and read addition expressions. EExxeerrcciissee Write and read subtraction expressions.
2 +2=4 6 - 2= 4
2 2 4added to makes a total of . 6 2 4subtracted from is .
2 +4= 6 7 - 3= 4
2 4 6added to makes a total of . 7 3 4subtracted from is .
74 NUMINO Challenge K2 75Operations
Use terminologies that indicate addition or subtraction to familiarize students with the
vocabulary that they can use to determine if they should add or subtract. For example, add,
put together, all together, subtract, decreased by, and less than are some of the terms that are
used to indicate addition or subtraction.
24 NUMINO Challenge K2
