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Overview
Overview
Taking jumps of 10 is an addition/subtraction strategy, where a student starts with a number and then takes whole-number jumps (by ten), followed by the remaining amount, using either a visual or mental number line.
Students may take jumps or count towards a decade number, and then take jumps from there.
Example: 25 + 27
An open number line is a good way to show this thinking. See these three examples of using this strategy to add 25 + 27. All three use the same basic strategy, but become more efficient.
S: “25 + 10 is 35, plus another ten is 45, then I counted up the seven by ones to get 52.
(Jumping by 10’s, then Counting on)
S: “25 + 10 is 35, plus another ten is 45, then 5 more gets me to 50, and 3 more to 52.” (Jumping by 10’s, then using Up over 10)
S: “25 + 20 is 45, then 5 more gets me to 50, and 2 more to 52.” (Jumping by a multiple of 10, then using Up over 10)
Getting to a Decade Number & Taking Jumps of 10
This is a closely related strategy, where a student decomposes the second number. They add ones onto the first number to get to a decade number, add the tens from the second number and then add any remaining ones.
25 + 27
Taking Jumps in Subtraction
When subtracting, students can jump down, or add up. Here are 2 ways to calculate 62 – 24
Removing
S: “I subtracted 24 by taking away 10’s then subtracted the 4 in parts - 62, 52, 42, 40, 38
62 – 24 = 38” (Jumping by 10’s, then using Down over 10)
Adding up
S: “I added up starting at 24, 34, 44, 54, 60, 62. I added 38 in total, so 62 – 24 = 38” (Jumping by 10’s, then using Up over 10)
Supporting Students with Taking Jumps of 10
Supporting Students with Taking Jumps of 10
Various models can be used to support students with taking jumps of 10.
Teachers often use hundreds charts for this, but students may continue to count by 1’s when adding or subtracting 10 on a hundreds chart.
Models like these ones, with ten-frames or base 10 materials (if students have used them), often help students discover the pattern - when adding or subtracting 10's to a given number, the ones digit remains the same.
Once students no longer try to count by 1's to add on the hundred's chart, this hundreds chart on Brainingcamp includes arrows to show addition or subtraction operations.
Games to Promote taking Jumps of 10
Games to Promote taking Jumps of 10
101 and Out
101 and Out
Students roll a die, and decide whether to use that as a number of tens or a number of ones.
Students keep doing this and keeping a running total by added the number of tens or ones to their previous total.
Players play for 6 rounds. The winner is the person who gets closest to 100 without going over at the end of the sixth round.
Roll to 100
Students roll a special die, labelled +1, -1, +10, -10, +11, -11 and race to get to the end of the end of a game board.
Make 10 and Add to the 10
Students take turns in a small group adding up to make decade numbers. Player 1 says a number less than 10, player 2 adds to to it make 10. Player 3 adds a new number (less that 10) and says the new running total, player 4 adds to that number to make 20. Players continue adding on to get to decade numbers.
Example
Player 1: "6"
Player 2: "4 because 6 + 4 = 10"
Player 3: "7, 10 + 7 = 17"
Player 4: "#, since 17 + 3 = 20"
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