Unit 01 // Session D // Extra practice 2
What you need: A 20-bead rekenrek with two rows of 10 beads, plus a pencil. Use the real rack for every question.
See groups of 5 and 10, build numbers to 20, and add without counting every bead one by one.
Build it without counting one bead at a time.
An adult says each number. Build it on the rack, then write how you saw it.
Read each rack without counting every bead.
Look for 5, 10, or the same amount on both rows.
Make ten, without changing the total.
Show 8 + 5 on separate rows. Slide 2 unused top beads left, and slide 2 used bottom beads back right. The same total now looks like 10 + 3.
| Build | Needs to make 10 | Left over | Total |
|---|---|---|---|
| 8 + 5 | 2 | 3 | 13 |
| 9 + 7 | 1 | 6 | 16 |
| 7 + 6 | 3 | 3 | 13 |
| 8 + 7 | 2 | 5 | 15 |
Use the two rows for doubles and near doubles.
For a double, show the same number on both rows. For a near double, build the double first, then move one more bead.
Build, solve, and say what you saw.
Use make ten, a double, or a near double. Circle the strategy after you solve.
Play: flash, cover, explain.
An adult builds one number, shows it briefly, then covers the rack with paper. Say the number and explain the groups you saw. There is no score.
The student builds and reads numbers to 20 without counting every bead, describes a number as 5 and some more or 10 and some more, and solves the addition facts by making ten or using a double.
If Donia begins counting beads one by one, reset the rack and ask only: What group can you see already? Follow with: Five and how many more? or Ten and how many more?
Use the rack for five to ten minutes at a time. Stop after a successful answer, then repeat questions 3 and 5 on another day.
MathNest · Unit 01 · Session D · Extra practice 2 · Rekenrek lab