This week, we have been working with various manipulatives to create combinations of numbers that together make ten. First, each student assembled a row of ten interlocking cubes. Together, we separated one cube at a time and counted how many had been moved and how many remained. Out loud, we would say, “un plus neuf sont dix (1+9=10)” and write the equation. The children noticed how gradually the number of cubes on one side decreased as the number of cubes on the other side increased. They pointed out patterns in our list of equations and recognized that the equations at the bottom of the list were simply the reverse of the equations at the top. That is, for example, that “deux plus huit (2+8)” is the same as “huit plus deux (8+2).” We emphasized that with each pair of numbers, the total always added up to ten. We continued by adding all our rows of cubes together and counted by tens up to 120. The children noticed how there are two groups of ten in vingt, three in trente, etc. They could see how this pattern continued past 100. Several students astutely noted that when we were counting by tens up to 120, we didn't have to re-count each individual cube, but rather we could use one group of ten and compare the height of this tower with the heights of all the other groups of ten. If a tower was too long or too short, we would know that it did not contain precisely 10 cubes. In a subsequent activity, the children threaded ten beads on a length of plastic lacing and separated one bead at a time, reviewing many of the same concepts. With our base ten number system, the number ten is of great significance. It is very helpful to readily be able to identify combinations of numbers that add up to ten.
The activities using interlocking cubes and beads addressed several specific expectations that fall under the “Number Sense and Numeration” strand of the Kindergarten math curriculum. Our students:
• demonstrated an understanding of number relationships for numbers from 0 to 10;
• investigated and developed strategies for composing and decomposing quantities to 10 using manipulatives;
• investigated addition and subtraction through the use of manipulatives;
• recognized some quantities without having to count, using strategies such as composing or decomposing numbers, and by subitizing.
They also practiced fine motor skills when they used their fingers to connect and disconnect the interlocking cubes and to thread the beads onto the string.
Have a great night!