Theme 5.  Addition and subtraction of the number 3

In the theme you learn:
• You will learn to find the sum of three addends;
• You will find out how to do addition and subtraction of the number 3 using a number line;
• You will practice calculating expressions with addition and subtraction of the number 3;
• You will find unknown parts and results of addition and subtraction;
• You will solve problems to find the sum, the difference, and to increase a number by a few units;
• You will practice comparing an expression and a number.