Mix Mountain — Lesson 67: Carry practice
Long sums with friends →Lesson 67: Abacus carrying practice for kids
Level 5, Mix Mountain. Tens that need a friend and tens that roll on. Then beat your best time!
What your child does, card by card
Carry practice. Practice day! PlayBuddy opens the lesson: “Practice time. Let's get quicker and better.”
First a reminder (“46 + 4: the ten needs a friend”): the beads build 46, 40, 90 and 50, ring by ring, while your child watches. 6 off the ones. The ten: top bead down, four tens off.
Try it: your child works out 47 + 8 and 100 - 1, with a green ring on the next bead to move.
Fast sums: a mission of 8 tasks with a clock against your child’s own best time. Your child must work out 48 + 5, 52 - 8, 99 + 1, 44 + 7, 50 - 4, 95 + 5, 100 - 3 and 46 + 9.
In Copy me the drawn hand holds up 55, 50 and 44 in turn, and your child copies each one in beads.
In your head: the abacus is covered and your child works out 46 + 4, 52 - 8 and 95 + 4, showing each answer on the drawn fingers.
You're ready! Carries on every rod.
What this lesson trains
16 answers, roughly five minutes: 43 moves of the beads, 19 of them with the top bead and 24 with bottom beads. Numbers reach 100, so all three rods work. Then 3 quick looks in your head. 10 of the 10 sums need a big friend (“+8 = −2 +10”, “−1 = −10 +9”, “+5 = −5 +10”, “−8 = −10 +2”, “+1 = −9 +10”, “+7 = −3 +10”, “−4 = −10 +6”, “−3 = −10 +7” and “+9 = −1 +10”); the others use free beads.
Your child’s first moves: work out 47 + 8 and 100 - 1.
Fingers and hands
Below the abacus the drawn hands show zero and 44, 46, 47, 48, 50, 51, 52, 53, 55, 95, 97 and 99 here, finger for bead: the left hand counts the tens, the right hand the ones.
+8 on the fingers: the right hand lets 2 go and the left hand opens one more finger for the ten (−2 +10). −1 on the fingers: the left hand closes one finger for the ten and the right hand shows 9 more (−10 +9). +5 on the fingers: the right hand lets 5 go and the left hand opens one more finger for the ten (−5 +10). −8 on the fingers: the left hand closes one finger for the ten and the right hand shows 2 more (−10 +2). +1 on the fingers: the right hand lets 9 go and the left hand opens one more finger for the ten (−9 +10). +7 on the fingers: the right hand lets 3 go and the left hand opens one more finger for the ten (−3 +10). −4 on the fingers: the left hand closes one finger for the ten and the right hand shows 6 more (−10 +6). −3 on the fingers: the left hand closes one finger for the ten and the right hand shows 7 more (−10 +7). +9 on the fingers: the right hand lets 1 go and the left hand opens one more finger for the ten (−1 +10).
Above 99 the drawn hands rest, faded, because ten fingers stop at 99; the abacus keeps going.
The fingers lead in Copy me (55, 50 and 44); the beads answer.
What PlayBuddy and PlayType say
PlayBuddy: “Sometimes the new ten needs a small friend too.”
Stars
Three stars for up to 1 slip in 16 answers, two stars for up to 4.