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46 Cards in this Set
- Front
- Back
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Add by combining one pair of numbers at a time.
24+31+90+67=? |
24+31=55
90+67=157 55+157=212 |
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Add by breaking numbers down into tens and ones.
17+55+39+45=? |
17+55+39+45=
10+7+50+5+30+9+40+5= 10+50+30+40+7+5+9+5= 10+50+30+40+12+14= 10+50+30+40+10+10+2+4= 60+70+20+6= 130+20+6= 150+6=156 |
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Add by making tens and breaking numbers down into tens and ones.
15+45+87=? |
15+45=60
60+87= 60+80+7= 140+7= 147 |
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Add by making tens and breaking numbers down into tens and ones.
36+18+42=? |
18+42=
10+40+8+2= 50+10= 60+36=96 |
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Add by working with easier numbers(i.e. 10, 15, 5, etc).
49+92=? |
49+92=
50+91= 50+90+1= 40+100+1= 140+1= 141 |
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Add by breaking these numbers into numbers that are easier to work with (i.e. 10, 15, 5, etc)
13+56=? |
13+56=
10+55+3+1= 65+4=69 |
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Add using a picture and equation.
427+201=? |
457+201=658
(picture shows groups of 4+2, 5+0 and 7+1) |
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Subtract using a picture and equation.
492-351=? |
492-351=141
(picture shows groups of 4-3, 9-5 and 2-1) |
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Add the ones, tens, and hundreds to find the sum.
529+173=? |
529+173=
500+100+20+70+9+3= 600+90+12= 600+90+10+2= 600+100+2= 700+2=702 |
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Subtract the ones, tens and hundreds to find the difference.
703-481=? |
703-481=
700-400-0-80-3-1= 700-300-100-80-3-1= 400-20-2= 380-2=378 |
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Mentally add.
168+10=? |
178
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Mentally add.
193+100=? |
293
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Mentally add.
277+10=? |
287
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Mentally add.
203+100=? |
393
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Mentally add.
375+10=? |
385
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Mentally add.
329+100=? |
429
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Mentally add.
444+10=? |
454
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Mentally add.
465+100=? |
565
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Mentally add.
500+10=? |
510
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Mentally add.
523+100=? |
623
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Mentally add.
619+10=? |
629
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Mentally add.
642+100=? |
742
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Mentally add.
731+10=? |
741
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Mentally add.
722+100=? |
822
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Mentally add.
883+10=? |
893
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Mentally add.
892+100=? |
992
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Mentally subtract.
831-10=? |
821
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Mentally subtract.
897-100=? |
797
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Mentally subtract.
714-10=? |
704
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Mentally subtract.
757-100=? |
657
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Mentally subtract.
613-10=? |
603
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Mentally subtract.
694-100=? |
594
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Mentally subtract.
533-10=? |
523
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Mentally subtract.
517-100=? |
417
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Mentally subtract.
470-10=? |
460
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Mentally subtract.
482-100=? |
382
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Mentally subtract.
321-10=? |
310
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Mentally subtract.
389-100=? |
289
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Mentally subtract.
274-10=? |
764
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Mentally subtract.
219-100=? |
119
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Mentally subtract.
159-10=? |
149
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Mentally subtract.
104-100=? |
4
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Explain why this solution is correct.
37+293= 30+7+200+90+3= 200+30+90+7+3= 200+30+ 90+10= 200+120+90+10= 200+100+20+90+10= 200+100+110+10= 200+100+100+10+10= 300+100+20= 400+20= 420 |
This solution is correct because you added the hundreds together, the tens together, and the ones together. When you added the ones together you had to make a ten and when you added the tens together you had to make a hundred and then when you added the new tens together you had to make another hundred. Then you added the new and original hundreds together and the new and original tens together to get 420.
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Explain why this solution is correct.
499+246= 500+245=745 |
This solution is correct because if you add one to one of the addends you can take one away from the other addend to even it out. Then you add the new numbers together because they are easier to add.
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Explain why this solution is correct.
728-417= 700-400-20-10-8-7= 300-10-1= 290-1= 289 |
This solution is correct because you subtracted hundreds from hundreds, tens from tens and ones from ones.
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Explain why this solution is correct.
683-255= 600+70+13 - 200+50+5= 600-200-70-50-13-5= 400-20-8=380-8=372 |
This strategy is correct because you took from the tens to make a group of 13 ones because you can't take 5 away from 3 but you can take 5 away from 13. It also works because you can subtract by breaking numbers into hundreds, tens, and ones in order to make it easier
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