Hi @tpeterson
Your problem is a challenging one as it practices many complements of 10!
I appreciate your descriptive text teaching a student how to add 9 + 6.
Hi @Michelle_Ellis
Your problem would be considered and intermediate level complements of 10 problem as it has a few complement movements, but not for each addend.
Hi @Mary_Tubilleja
I love the idea of pairing the abacus and calculator together.
Your problem has complements of 10 and it fine up until you try to add the 7. At this point you are moving beyond complements of 10. I would suggest changing the 7 to a 9 and then adding 3 instead of subtracting 3. This would be 2 + 8 - 4 + 9 + 3
Hi @sarah.whittington
I am so happy the abacus is gaining value in your eyes. You also have an excellent beginner complements of 10 problem.
Hi @Kim_Shoffner
You have a creative way of incorporating the calculator and the abacus in one lesson. Your example complements of 10 problem is quite complex and would be given when a student has learned many complements already. You gave an excellent description of the steps in your own problem. What would be the steps for adding nine to six?
Welcome to the Hive @jfbamber
I have added a few calculator activities to my toolbox - thanks for the ideas!
Your complements of 10 problem is great for isolating the 4-6 partners of 10.
To add 9 to 6, set 6 on the abacus by pinching the 5 bead with the right pointer finger down toward the separation bar and the one bead with the right thumb up toward the separation bar at the same time. I do not have 9 to add to the first column so I would make a ten pair compliment exchange by setting a one bead in the second column by pushing it up with the right thumb toward the separation bar and removing 9’s ten pair compliment of 1 in the first column by pushing down a one bead with the right pointer finger. I read the answer as 15.
Hi @Kim_Shoffner
You have wonderfully descriptive steps in your instructions for adding 9 to 6. Want to try your hand and creating a math problem that teaches the complements of 10?
7 + 9 + 5 = 21
I set 7 on the abacus by pinching the 5 bead down toward the separation bar with the right pointer finger and pinching the 2 one beads up toward the separation bar with the right thumb at the same time in the first column. I do not have 9 to set in the first column so I set one bead in the second column by pushing it up toward the separation bar with the right thumb. I remove 9’s 10 pair compliment 1 in the first column by pushing it down away from the separation bar with the right pointer finger leaving the subtotal 16. The 5 bead is already set in the first column so I have to set a one bead in the second column by pushing it up toward the separation bar with the right thumb and removing 5’s 10 pair compliment 5 by pushing the 5 bead in the first column up away from the separation bar with the right pointer finger. I read the answer 21.
Nice work, @Kim_Shoffner
Your problem has two complements of ten, the 9 and 1 and the 5 and 5.