classroom.jpgUnit 5 reviews and builds on children's knowledge of tens-and-ones groupings to 100. Children first perform simple addition with tens and ones. They then explore relationships that will help them gain automaticity with greater numbers, such as the relationship between ten-partners and hundred-partners (6 + 4 = 10 and 60 + 40 = 100). Children also engage in extensive practice sequencing 2-digit numbers to develop facility in counting to 100.

Dimes, Nickels, and Pennies
Children have previously worked only with nickels and pennies. In Unit 5, they are introduced to dimes as well. Initially, they make 2-digit coin amounts just using dimes and pennies. These activities map directly into their knowledge of tens and extra ones. Children progress to using the three coin types to show monetary amounts. Their goal is to make a 2-digit amount with the fewest coins possible. In this unit, children are also introduced to the dollar in terms of 100 pennies and 10 dimes.

Teen Solution Methods
In the previous unit, children explored methods of adding two numbers that resulted in a teen total. In Unit 5, they build on this foundation. They explore methods of subtracting from a teen total and finding an unknown addend for a teen total. This is integrated with story problems and coin problems.

Finding Patterns and Relationships
Recognizing repeating number patterns helps children master the numbers from 1 to 100 and also serves as a computational aid. In Unit 5, children explore patterns and relationships in various ways. In Unit 4, children added numbers such as 30 + 40, 30 + 4. and 38 + 4. In Unit 5, they will learn to add a ten to any 2-digit number, such as 38 + 10. Then they will add multiples of ten to any 2-digit number, such as 38 + 40. These activities are reinforced with the Hundred Grid, which allows children to see the ten-based patterns in sequence. Any computation done on the grid is also performed either with sticks and circles or by counting on.

Fuson, Karen, Math Expressions, Unit 5 Overview