Sharing Garden — Lesson 96: Sharing a two-digit number
When the tens leave some over →Lesson 96: Dividing two-digit numbers on an abacus
Level 8, Sharing Garden. Share the tens. Then share the ones. Add what each one gets.
What your child does, card by card
Sharing a two-digit number. 84 ÷ 4: the tens first, then the ones. PlayBuddy opens the lesson: “Share the tens first, then the ones.”
84 ÷ 4: four friends. Give each one a ten. The beads work the column line by line, 84, 44, 4 and zero, while the sum sheet below lights each line and ticks it; “1 ten each: 44 left”, “2 tens each: 4 left”, “1 one each: 0 left” and “Each gets 21” light up as the total grows. Count what each friend has.
2 tens each, in one go: 4 × 20 = 80 off. Then 4 × 1 = 4 off. The beads work the column line by line, 84, 4 and zero, while the sum sheet below lights each line and ticks it; “Start: 84”, “4 × 20 off: 4 left”, “4 × 1 off: 0 left” and “Each gets 21” light up as the total grows. Each gets 20 and 1: that is 21.
First a reminder (“69 ÷ 3”): the beads build 69 and 9, ring by ring, while your child watches. 3 × 20 off, then 3 × 3 off. Each gets 23.
Try it: your child works out 84 ÷ 4, 48 ÷ 2 and 93 ÷ 3, with a green ring on the next bead to move.
Then a short practice without rings: work out 55 ÷ 5, 88 ÷ 4 and 86 ÷ 2, each round starting from its own number.
Then the beads hide and the sums 80 ÷ 4, 90 ÷ 3 and 50 ÷ 5 are done in the head, the answer picked from 10, 20 and 30.
You're ready! Share the tens first, then the ones.
What this lesson trains
27 answers, roughly five minutes: 31 moves of the beads, 9 of them with the top bead and 22 with bottom beads. 6 of them are clears. The largest is 93: tens and ones. Then 3 quick looks in your head.
It starts with doing: work out 84 ÷ 4, 48 ÷ 2 and 93 ÷ 3.
The sum sheet
The lower window shows the column as a child would write it on paper: one number under another, the current line in yellow, ticks on the lines done. The abacus carries the running total from line to line.
What PlayBuddy and PlayType say
PlayBuddy: “Share the tens first, then the ones.”
PlayType: “One ten each: four tens go. One more ten each: four more go. Then one each. Twenty-one each!”
PlayBuddy: “Big part first, then the small part.”
Stars
27 answers: 2 slips still give three stars; up to 6, two stars.