# 2.3 - Ordinal positions

The student will

a)  count and identify the ordinal positions first through twentieth, using an ordered set of objects; and

b)  write the ordinal numbers 1st through 20th.

### BIG IDEAS

• Knowing ordinal numbers is essential to spatial (lining up), temporal (second hour of the day) and personal (I came first)

• So that I can use ordinal numbers  everyday when we do things like lining up and waiting in line,  finishing a race, or figuring out what grade someone is in

### UNDERSTANDING THE STANDARD

 The cardinal and ordinal understanding of numbers is necessary to quantify, measure, and identify the order of objects.The ordinal meaning of numbers is developed by identifying and verbalizing the place or position of objects in a set or sequence (e.g., a student’s position in line when students are lined up alphabetically by first name).The ordinal position is determined by where one starts in an ordered set of objects or sequence of objects (e.g., from the left, right, top, bottom).Ordinal position can also be emphasized through sequencing events (e.g., days in a month or events in a story).Practical applications of ordinal numbers can be experienced through calendar and patterning activities.

### ESSENTIALS

The student will use problem solving, mathematical communication, mathematical reasoning, connections, and representations to

• Count an ordered set of objects, using the ordinal number words first through twentieth. (a)
• Identify the ordinal positions first through twentieth, using an ordered set of objects presented in lines or rows from
• left to right;
• right to left;
• top to bottom; and
• bottom to top. (a)
• Write 1st, 2nd, 3rd, through 20th in numerals. (b)

### KEY VOCABULARY

Updated: Aug 22, 2018