Learn how to add basic num­bers togeth­er into a com­bined val­ue. When we do this, we write num­bers larg­er than 9 with two or more dig­its. Learn how we com­bine larg­er num­bers by group­ing num­bers into groups of tens. This is called the dec­i­mal system. 

Top­ics from Unit 1: 

• • • • • • • • addi­tion
              • place val­ue
              • car­ry­ing
              • word prob­lems

Unit 1 Lesson contents: 

Ray’s Les­son 4 instruc­tion­al video

Assign­ment — com­plete exer­cis­es for les­son 4

Activ­i­ty — Use Cuise­naire rods to prac­tice show­ing car­ry­ing with addi­tion problems