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Published byPeter Ward Modified over 9 years ago
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Adding Two Numbers Directly.Another term for directly is “no synthesis.” When adding directly all the beads you need are available to push to the separation bar. From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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3+1 = 4 Set three 1-beads in the units column. Ask: “Can I add 1 directly?” Answer” “Yes I can.” Set a 1-bead in the units column. You now have 4 beads in the unit column. Sum = 4 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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5+3 = 8 Set a 5-bead in the units column. Ask: “Can I add 3 directly?” Answer” “Yes I can.” Set three 1-beads in the units column. You now have 8 beads in the units column. Sum = 8 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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Set two 1-beads in the units column. Ask: “Can I add 2 directly?” Answer” “Yes I can.” Set two 1-beads in the units column. You now have 4 beads in the units column. Sum = 4 2+2 = 4 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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Try doing 6 + 3 on your own. Say the steps! From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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6 + 3 = 9 Set a 5-bead and a 1-bead in the units column. Ask: “Can I add 3 directly?” Answer” “Yes I can.” Set three 1-beads in the units column. You now have 9 beads in the units column. Sum = 9 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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30 + 50 = 80 Set three 1-beads in the tens column. Ask: “Can I add 50 directly?” Answer” “Yes I can.” Set a 5-bead in the tens column. You now have 8 beads in the tens column. Sum = 80 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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Try doing 60 + 10 on your own. Say the steps! From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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60 + 10 = 70 Set a 5-bead and a 1-bead in the tens column. Ask: “Can I add 10 directly?” Answer” “Yes I can.” Set a 1-bead in the tens column. You now have 7 beads in the tens column. Sum = 70 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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45 + 3 = 48 Set four 1-beads in the tens column and a 5-bead in the units column. Ask: “Can I add 3 directly?” Answer” “Yes I can.” Set three 1-beads in the units column. Sum = 48 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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27 + 60 = 87 Set two 1-beads in the tens column and 7 beads in the units column. Ask: “Can I add 60 directly?” Answer” “Yes I can.” Set a 5-bead and a 1-bead in the tens column. Sum = 87 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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55 + 20 = 75 Set a 5-bead in the tens column and a 5-bead in the units column. Ask: “Can I add 20 directly?” Answer” “Yes I can.” Set two 1-beads in the tens column. Sum = 75 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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13 + 26 = 39 Set a 1-bead in the tens column and three 1-beads in the units column. Ask: “Can I add 20 directly?” Answer” “Yes I can.” Set two 1-beads in the ten column. Ask “Can I add 6 directly?” Answer” “Yes I can.” Set a 5-bead and a 1-bead in the units column. Sum = 39 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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46 + 52 = 98 Set four 1-beads in the tens column and 6 beads in the units column. Ask: “Can I add 50 directly?” Answer” “Yes I can.” Set a 5-bead in the tens column. Ask “Can I add 2 directly?” Answer” “Yes I can.” Set two 1-beads in the units column. Sum = 98 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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247 + 601 = 848 Set two 1-beads in the hundreds column, four 1-beads in the tens column and 7 beads in the units column. Ask: “Can I add 600 directly?” Answer” “Yes I can.” Set 600 in the hundred columns. Ask: “Can I add 0 directly?” Answer” “Yes I can.” Set 0 by tapping the silver bar in the tens column. Ask: “Can I add 1 directly?” Answer” “Yes I can.” Set 1 in the units column. Sum = 848 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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567 +321 = 888 Set a 5-bead in the hundreds column, 6 beads in the tens column and 7 beads in the units column. Ask: “Can I add 300 directly?” Answer” “Yes I can.” Set 300 in the hundred columns. Ask: “Can I add 20 directly?” Answer” “Yes I can.” Set 20 in the tens column. Ask: “Can I add 1 directly?” Answer” “Yes I can.” Set 1 in the units column. Sum = 888 From http://www.uabacus.arizona.edu/ Developed by Dr. L. Penny Rosenblum
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