⑴2,000{#blank#}1{#/blank#}     A. eight thousand

⑵8,000{#blank#}2{#/blank#}     B. two thousand

⑶40,000{#blank#}3{#/blank#}    C. forty thousand

⑷800{#blank#}4{#/blank#}       D. eight hundred

{#blank#}1{#/blank#}one

{#blank#}2{#/blank#}ten

{#blank#}3{#/blank#}eleven

{#blank#}4{#/blank#}seven

{#blank#}5{#/blank#}twenty

例：one+one=2

two+nine= {#blank#}1{#/blank#}                                                                
five+five= {#blank#}2{#/blank#}

eight-one= {#blank#}3{#/blank#}                                                                
four×three= {#blank#}4{#/blank#}