Students need to be able to express a fraction with a denominator of 10 as an equivalent fraction with a denominator of 100 and use this technique to add fractions.
This is what I did...
Lesson 1 First we created equivalent fractions with denominators of 10 and 100 by shading in base 10 blocks. Students looked at the shapes and realized that they were different in parts but equaled the same amount and were the same size.
Ex...3/10 = 30/100
Lesson 2 We continued this process reversing it from 100 to 10 and students did use the base ten blocks if necessary. Students were asked how to explain this process and they used the models or drew pictures of the models to explain their thinking. I also used money for some students-dimes and pennies.
Lesson 3 Next we moved on to adding fractions of 10 and 100 by using base ten models to create equivalent fractions. I spent 2 days on this concept and also reviewed this in small group. I also used money to help with this concept. Students also practiced subtration as well.
Ex...3/10 + 4/100 = 30/100 + 4/100 = 34/100
3/10- 4/100 = 30/100 - 4/100 = 26/100
Lesson 4 Students then took their knowledge and applied it to solve problems that involved this skill.
Center Activities I also created a matching game that involved addition with deominators of 10 and 100 and I used that in small group and whole group. Students would get a card and they would need to find their partner. Once everyone found their partner they spoke about their answer and how they knew it was correct.
I also created a matching game that involved money with dimes and pennies so that students related the concept to something else besides base ten models.
I hope this helps you!