Math Boot Camp 0038-001
Japanese ed. / Amazon Kindle / 1-digit negative plus 1-digit addition + 1-digit negative minus 1-digit subtraction + 1-digit negative minus 1-digit negative subtraction

[Stage 2]

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 ①: ( 7.7 sec. )

 ②: ( 7.6 sec. )

 ③: ( 8.0 sec. )

 ④: ( 10.0 sec. )

 ⑤: ( 7.9 sec. )

 ⑥: ( 9.0 sec. )

 ⑦: ( 8.2 sec. )

 ⑧: ( 9.3 sec. )

 ⑨: ( 8.2 sec. )

 ⑩: ( 7.3 sec. )

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