Lesson 93: Division for kids on an abacus: sharing
Level 8, Sharing Garden. Sharing fairly means everyone gets the same.
What your child does, card by card
Sharing: what dividing means. 12 cookies for 3 friends. PlayType opens the lesson: “Twelve cookies for three friends. Let us share them fairly.”
Share 12 cookies: one cookie each: 3 cookies go. The beads work the column line by line, 12, 9, 6, 3 and zero, while the sum sheet below lights each line and ticks it; “1 each: 9 left”, “2 each: 6 left”, “3 each: 3 left” and “4 each: 0 left” light up as the total grows. Count the rounds.
12 ÷ 3 = 4: ÷ means shared by. The beads work the column line by line, zero, 4, 8 and 12, while the sum sheet below lights each line and ticks it; “12 cookies”, “3 friends” and “4 each” light up as the total grows. Three friends with 4 each: 4 + 4 + 4 = 12.
10 ÷ 2: the abacus makes 10, 8, 6, 1, 4 and 2 by itself, a green ring on each bead just before it moves, and the sum sheet below ticks each line. One each: 2 go. Five rounds: 5 each.
In Try it a green ring marks the next bead while your child works out 12 - 3, 9 - 3, 6 - 3, 3 - 3, 12 ÷ 3, 15 - 5, 10 - 5, 5 - 5 and 15 ÷ 5.
The tiny practice drops the ring: work out 8 - 2, 6 - 2, 4 - 2, 2 - 2, 8 ÷ 2, 9 - 3, 6 - 3, 3 - 3 and 9 ÷ 3, each round starting from its own number.
In your head: the abacus is covered and your child works out 12 ÷ 3, 10 ÷ 2 and 15 ÷ 5, picking each answer from 3, 4 and 5.
You're ready! Sharing fairly: one each, again and again.
What this lesson trains
21 answers in about five minutes. The tasks take 24 bead moves in all: 7 with a top bead and 17 with bottom beads. 4 of them are clears. The largest is 15: tens and ones. Then 3 quick looks in your head. Friends do 5 of the 18 sums, by −3 = −10 +7, −3 = −5 +2, −5 = −10 +5 and −2 = −5 +3.
Your child’s first moves: work out 12 - 3, 9 - 3, 6 - 3, 3 - 3, 12 ÷ 3, 15 - 5, 10 - 5, 5 - 5 and 15 ÷ 5.
The sum sheet
Below the abacus a sum sheet replaces the hands: it writes the column out, lights the line your child is on and ticks each line done; the total appears after the last line. The beads hold the running total the whole way down.
What PlayBuddy and PlayType say
PlayType: “Twelve cookies for three friends. Let us share them fairly.”
PlayType: “One cookie each: three cookies go. Again, again, and again. Four times: four cookies each!”
PlayBuddy: “Dividing means sharing fairly.”
Stars
Three stars for up to 2 slips in 21 answers, two stars for up to 5. A number counts as a slip only when it stays wrong for a moment and is not on the way to the answer, so a child who moves beads one at a time is never marked down. After two slips on one task the green ring comes back.
About Sharing Garden
Sharing Garden is Level 8 of nine (grade 4 to 5): exact division, checked by multiplying back. In your head: sharing sums in your head.